I am writing an web app that saves html to onenote. In order to save math formulas, I plan to convert math formulas to svg by MathJax.js and then convert svg to png, because the html/css supported in onenote api is limited.
But it seems the svg generated by MathJax.js in browser is not a valid svg. I tested it with a simple math formula: $$a^2 + b^2 = c^2$$ (demo code) and copy the svg to jsfiddle and it displays nothing.
Then I tried to write a MathJax-node demo and copy the svg to jsfiddle again, it looks good. Here is my demo code, it's almost the same as the GitHub repo demo:
// a simple TeX-input example
const fs = require('fs')
var mjAPI = require("mathjax-node");
mjAPI.config({
MathJax: {
// traditional MathJax configuration
}
});
mjAPI.start();
var yourMath = String.raw`a^2 + b^2 = c^2`
mjAPI.typeset({
math: yourMath,
format: "TeX", // or "inline-TeX", "MathML"
svg: true, // or svg:true, or html:true
}, function (data) {
if (!data.errors) {console.log(data.svg)}
// will produce:
// <math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
// <mi>E</mi>
// <mo>=</mo>
// <mi>m</mi>
// <msup>
// <mi>c</mi>
// <mn>2</mn>
// </msup>
// </math>
fs.writeFile('math.txt', data.svg, (error) => {
console.log(error)
})
});
I also tested two svg with cloudconvert, it's the same result. Why are the two svg different? Do I miss something?
The difference is due to a specific setting: useGlobalCache
By default, MathJax (docs) sets this to true while mathjax-node (docs) sets this to false.
On the server MathJax-node does not have any document context and produces self-contained SVGs. On the client, MathJax has a full document context and thus can re-use the SVG paths across equations.
I used to compile and insert JSX components via
<div key={ ID } dangerouslySetInnerHTML={ { __html: HTML } } />
which wrapped my HTML into a <div>:
<div>my html from the HTML object</div>
Now react > 16.2.0 has support for Fragments and I wonder if I can use that somehow to avoid wrapping my HTML in a <div> each time I get data from the back end.
Running
<Fragment key={ ID } dangerouslySetInnerHTML={ { __html: HTML } } />
will throw a warning
Warning: Invalid prop `dangerouslySetInnerHTML` supplied to `React.Fragment`. React.Fragment can only have `key` and `children` props.
in React.Fragment
Is this supported yet at all? Is there another way to solve this?
Update
Created an issue in the react repo for it if you want to upvote it.
Short Answer
Not possible:
key is the only attribute that can be passed to Fragment. In the
future, we may add support for additional attributes, such as event
handlers.
https://reactjs.org/docs/fragments.html
You may want to chime in and suggest this as a future addition.
https://github.com/facebook/react/issues
In the Meantime
You may want to consider using an HTML parsing library like:
https://github.com/remarkablemark/html-react-parser
Check out this example to see how it will accomplish your goal:
http://remarkablemark.org/blog/2016/10/07/dangerously-set-innerhtml-alternative/
In Short
You'll be able to do this:
<>
{require('html-react-parser')(
'<em>foo</em>'
)}
</>
Update December 2020
This issue (also mentioned by OP) was closed on Oct 2, 2019. - However, stemming from the original issue, it seems a RawHTML component has entered the RFC process but has not reached production, and has no set timeline for when a working solution may be available.
That being said, I would now like to allude to a solution I currently use to get around this issue.
In my case, dangerouslySetInnerHTML was utilized to render plain HTML for a user to download; it was not ideal to have additional wrapper tags included in the output.
After reading around the web and StackOverflow, it seemed most solutions mentioned using an external library like html-react-parser.
For this use-case, html-react-parser would not suffice because it converts HTML strings to React element(s). Meaning, it would strip all HTML that wasn't standard JSX.
Solution:
The code below is the no library solution I opted to use:
//HTML that will be set using dangerouslySetInnerHTML
const html = `<div>This is a div</div>`
The wrapper div within the RawHtml component is purposely named "unwanteddiv".
//Component that will return our dangerouslySetInnerHTML
//Note that we are using "unwanteddiv" as a wrapper
const RawHtml = () => {
return (
<unwanteddiv key={[]}
dangerouslySetInnerHTML={{
__html: html,
}}
/>
);
};
For the purpose of this example, we will use renderToStaticMarkup.
const staticHtml = ReactDomServer.renderToStaticMarkup(
<RawHtml/>
);
The ParseStaticHtml function is where the magic happens, here you will see why we named the wrapper div "unwanteddiv".
//The ParseStaticHtml function will check the staticHtml
//If the staticHtml type is 'string'
//We will remove "<unwanteddiv/>" leaving us with only the desired output
const ParseStaticHtml = (html) => {
if (typeof html === 'string') {
return html.replace(/<unwanteddiv>/g, '').replace(/<\/unwanteddiv>/g, '');
} else {
return html;
}
};
Now, if we pass the staticHtml through the ParseStaticHtml function you will see the desired output without the additional wrapper div:
console.log(ParseStaticHtml(staticHtml));
Additionally, I have created a codesandbox example that shows this in action.
Notice, the console log will throw a warning: "The tag <unwanteddiv> is unrecognized in this browser..." - However, this is fine because we intentionally gave it a unique name so we can easily differentiate and target the wrapper with our replace method and essentially remove it before output.
Besides, receiving a mild scolding from a code linter is not as bad as adding more dependencies for something that should be more simply implemented.
i found a workaround
by using react's ref
import React, { FC, useEffect, useRef } from 'react'
interface RawHtmlProps {
html: string
}
const RawHtml: FC<RawHtmlProps> = ({ html }) => {
const ref = useRef<HTMLDivElement>(null)
useEffect(() => {
if (!ref.current) return
// make a js fragment element
const fragment = document.createDocumentFragment()
// move every child from our div to new fragment
while (ref.current.childNodes[0]) {
fragment.appendChild(ref.current.childNodes[0])
}
// and after all replace the div with fragment
ref.current.replaceWith(fragment)
}, [ref])
return <div ref={ref} dangerouslySetInnerHTML={{ __html: html }}></div>
}
export { RawHtml }
Here's a solution that works for <td> elements only:
type DangerousHtml = {__html:string}
function isHtml(x: any): x is DangerousHtml {
if(!x) return false;
if(typeof x !== 'object') return false;
const keys = Object.keys(x)
if(keys.length !== 1) return false;
return keys[0] === '__html'
}
const DangerousTD = forwardRef<HTMLTableCellElement,Override<React.ComponentPropsWithoutRef<'td'>,{children: ReactNode|DangerousHtml}>>(({children,...props}, ref) => {
if(isHtml(children)) {
return <td dangerouslySetInnerHTML={children} {...props} ref={ref}/>
}
return <td {...props} ref={ref}>{children}</td>
})
With a bit of work you can make this more generic, but that should give the general idea.
Usage:
<DangerousTD>{{__html: "<span>foo</span>"}}</DangerousTD>
I'm making a page builder type thing. For normal view the iframe needs to resize accordingly, but for mobile / tablet views it needs to be a set size.
using iframe-resizer https://github.com/davidjbradshaw/iframe-resizer by #david-bradshaw
parent window:
<script type="text/javascript" src="javascript/iframeResizer.min.js"></script>
....
$("iframe")[0].iFrameResize({
checkOrigin: false,
enablePublicMethods : true,
heightCalculationMethod: "bodyScroll",
});
....
The viewpoint size changer does this :
// set the iframes width and height "before" iframeresizer does stuff to make it look seemless
_this.editor.css({
"width":mapper[size].width,
"height":mapper[size].height
})
Only way I saw the .size() working is from the iframe itself
// fire off a sendMessage cause only way i saw .size() working is from the iframe itself
_this.editor[0].iFrameResizer.sendMessage({
"width":mapper[size].width,
"height":mapper[size].height,
"forceSize":true
});
iframe window
<script>
var iFrameResizer = {
messageCallback: function(message){
console.log("messageCallback")
console.log(message)
if (message.forceSize==true){
console.log(window.parentIFrame)
window.parentIFrame.autoResize(false);
window.parentIFrame.size(message.height); // Set height to 100px
} else {
// apply auto resizing again
}
}
}
</script>
<script type="text/javascript" src="javascript/iframeResizer.contentWindow.min.js"></script>
I was hoping for an easier way like on parent disableIframeResizer() or something, or being able to set .size() from parent since that's where the choose your viewpoint parts live.I can't seem to figure it out :(
My issue is: I need to somehow tell the iframe not to do its resizing when forceSize = true and then when the message comes in then to resize accordingly .
Thanks for a pretty decent library tho!
I don't think I understand your question 100%. But I tried to answer your question as best as I understood.
You can set an iframe's size really simply in html. You can also do it with the help of CSS.
You could do this: <iframe href="https://google.com" width="100%" height="100%">Your Browser Does Not Support Iframe</iframe>.
You could also set the exact diameter like this: <iframe href="https://google.com" width="300px" height="100px">Your Browser Does Not Support Iframe</iframe>
You could also use php to automatically change the diameter of it.
How can I add a phone number to a website that is clickable but hides the link when I'm browsing on a website that doesn't support touch.
I could use Modernizr to set it up although. I don't know how.
<p><img src="assets/images/bt_calltoaction.gif" alt="View Projects" width="306" height="60"></p>
Could you just have the code in twice? i.e...
<div class="desktoptel">0800 000 000</div>
<div class="mobiletel"><a href="tel:0800-000-000">0800-000-000</div>
Then just 'display:none;' on the relevant class depending on your browser sizes?
I was just dealing with this issue, looking up solutions, and I found this thread (and a few others). I have to confess that I couldn't get any of them to work properly. I'm sure I was doing something wrong, BUT I did figure out a cheat.
As others have pointed out, changing the CSS to hide the visible link indication (color, text-decoration, cursor) is the first and easiest step. The cheat is to define a title for the tel link.
<p>Just call us at <a class="cssclassname" href="tel:18005555555"
title="CLICK TO DIAL - Mobile Only">(800) 555-5555</a>.</p>
By doing this, not only is the visible indicator of a link disguised (via CSS - see examples from others), but if someone does hover over the link, the title will pop up and say "CLICK TO DIAL - Mobile Only". That way, not only is there a better user experience, but your client doesn't accuse you of having a broken link!
For me the easiest, yet simplest method without any new classes / setup is via css:
a{
color: #3399ff;
}
a[href^="tel"]:link,
a[href^="tel"]:visited,
a[href^="tel"]:hover {
text-decoration: none;
color: #000;
pointer-events: none;
cursor: default;
}
/* Adjust px here (1024px for tablets maybe) */
#media only screen and (max-device-width: 480px) {
a[href^="tel"]:link,
a[href^="tel"]:visited,
a[href^="tel"]:hover {
text-decoration: underline;
color: #3399ff;
pointer-events: auto;
cursor: pointer;
}
}
Html just goes like this:
(+12)3 456 7
This works for modern browsers & IE 11+. If you need to include 8 < IE < 11 add the following to your javascript, since pointer-events dont work in IE:
var msie = window.navigator.userAgent.indexOf("MSIE ");
if (msie > 0){
var Elems = [], Tags = document.querySelectorAll("a[href^='tel']");
//Nodelist to array, so we're able to manipulate the elements
for (var i = 0; i < Tags.length; i++ ) {
Elems[ i ] = Tags[ i ];
}
for(var i = 0; i < Elems.length; i++){
Elems[ i ].removeAttribute('href');
}
}
EDIT: i found another answer on another thread, that may be useful for you - SO - Answer
I recently had this same problem. This problem is all over stackoverflow and everywhere else. How do you hide 'tel:' prefix and keep it from blowing up in regular browsers. There's no good single answer.
I ended up doing it this way:
first I use metalanguage to filter browser vs mobile (like php/coldfusion/perl) based on useragent string:
regular exp match for "/Android|webOS|iPhone|iPad|BlackBerry/i",CGI.HTTP_USER_AGENT
that gives me an if/else condition for desktop browser vs phone.
Next, my href tag looks like this: <a class="tel" id='tel:8005551212' href=''>800-555-1212</a>
Use CSS to style the .tel class in desktop stylesheet so it doesn't look like a link to desktop browsers. the phone number can still be clicked but its not obvious, and it wont do anything:
/* this is in default stylesheet, styles.css: */
.tel{
text-decoration:none;
color: #000;
cursor:default;
}
/* it should be re-styled in mobile css: */
.tel{
text-decoration: underline;
color: #0000CC;
cursor:auto;
}
Finally, I do a little jquery on the mobile links. The jQuery gets the id from the a.tel class, and inserts it into the href property, which makes it clickable for phone users.
The whole thing looks like this:
<!-- get regular CSS -->
<link rel="stylesheet" href="styles/styles.css" type="text/css" media="Screen" />
<!-- get user agent in meta language. and do if/else on result.
i'm not going to write that part here, other than pseudocode: -->
if( device is mobile ) {
<!-- load mobile CSS -->
<link rel="stylesheet" href="styles/mobile.css" type="text/css" media="handheld" />
<!-- run jQuery manipulation -->
<script>
$(function(){$('a.tel').prop('href',$('a.tel').prop('id'));});
</script>
}
<p> Call us today at <a class="tel" id='tel:8005551212' href=''>800-555-1212</a>!</p>
One caveat to this approach: id's should be unique. If you have duplicate phone numbers on a page that you want to link, change the id to name, then you use jQuery to loop through them.
You could use css media queries to control when its viewed as link and when not.
#media(min-width:768px){
a[href^="tel:"] {
pointer-events: none;
}
}
anything below 768px will work as link, above that, just as text.
if you just wanted to disable the click on the mobile screens:
if(typeof window.orientation !== 'undefined'){
$('a[href^="tel:"]').on('click', function(e){
e.preventDefaults();
});
}
Hope this helps :)
I've had success with this using Modernizr, specifically the touch test. It's not a perfect solution in that it doesn't do anything to help tablets or touch-enabled laptops, but it works in most desktop browsing situations.
HTML:
Call us at: 1-800-BOLOGNA
CSS:
.no-touch a.call-us {
color: black; /* use default text color */
pointer-events: none; /* prevents click event */
cursor: text; /* use text highlight cursor*/
}
The above CSS targets links with class="call-us" on non-touch devices which covers the majority of desktops.
Note that pointer-events is supported in all modern browsers but IE only supports it in versions 11+. See the compatibility chart.
Another solution, still imperfect, would be to use Modernizr.mq along with Modernizr.touch to detect screen width and touch capability and then inject the phone link with jQuery. This solution keeps the phone link out of the source code and then only appears on touch devices smaller than a certain width (say 720px which will probably cover most phones but exclude most tablets).
Ultimately, it's up to the browser vendors to come up with a bulletproof solution here.
I found the best way. I get that this is old, but I found a very easy way of doing this.
Using this code below
888-555-5555
//This is the logic you will add to the media query
.not-active {
pointer-events: none;
cursor: default;
}
In your CSS make use of media queries.
So make a media query for all desktops
#media only screen and (min-width: 64em) {
/* add the code */
.not-active {
pointer-events: none;
cursor: default;
}
}
Now all desktop sized pages wont be able to click on it.
it seems this could be done with a simple media query for most browsers. Something like this is working like a charm for me:
<style type="text/css">
#mobil-tel {
display:none;
}
#media (max-width: 700px) {
#mobil-tel {
display:block;
}
#desktop-tel{
display:none;
}
}
</style>
and on the desktop link, leave out the 'href', on the mobile link, put in the 'href'.
Just thought I would add my two-cents worth to (what is turning out to be a rather lengthy) discussion.
I basically use the onClick event (on the link) to execute Javascript to return a boolean true or false. If the return value is true, i.e. some variable or function that tests if the device is a phone returns a value true, then the href URL is followed by the browser. If the the return value is false, then the href URL becomes, in effect, inactive. (Standard HTML behavior, way before HTML5.)
Here is what I mean:-
<html>
<head>
<title>tel markup example</title>
<script src="http://code.jquery.com/jquery-2.1.0.min.js"></script> <!-- Does not really matter what version of jQuery you use -->
<script>
var probablyPhone = ((/iphone|android|ie|blackberry|fennec/).test(navigator.userAgent.toLowerCase()) && 'ontouchstart' in document.documentElement);
function initialize() {
if ( !probablyPhone ) {
alert ("Your device is probably not a phone");
( function( $ ) {
$( '.call' ).css ( "text-decoration", "none" );
$( '.call' ).css ( "color", "black" );
$( '.call' ).css ( "cursor", "default" );
} )( jQuery );
}
}
</script>
</head>
<body onLoad="initialize();">
Please ring (some fictitious number in Australia): +61 3 9111 2222
</body>
</html>
Note that I also added some re-formatting of the link to make it appear to the user as if it's just ordinary text.
Here is a gist I created.
Just to finish this post/ answer, credit for writing succinct JavaScipt code for detecting a phone (based on the user agent and the ontouchstart event) goes to a fellow Melbournian rgb in this stackoverflow post
Here is a simple jquery-based solution which I developed to solve this problem. See code comments for explanation.
https://jsfiddle.net/az96o8Ly/
// Use event delegation, to catch clicks on links that may be added by javascript at any time.
jQuery(document.documentElement).on('click', '[href^="tel:"]', function(e){
try{
// These user-agents probably support making calls natively.
if( /Android|webOS|iPhone|iPad|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) ) {
// Do nothing; This device probably supports making phone calls natively...
} else {
// Extract the phone number.
var phoneNumber = jQuery(this).attr('href').replace('tel:', '').trim();
// Tell the user to call it.
alert("Please call "+phoneNumber);
// Prevent the browser popup about unknown protocol tel:
e.preventDefault();
e.stopPropagation();
}
} catch(e){
console.log("Exception when catching telephone call click!", e);
}
});
My approach is similar to another approach above; there are a few considerations I take into account:
As we know, there is no good programmatic way to detect support. This is a rare case where we are forced to parse the UserAgent string.
This should be client side; there is no need for server side detection.
There are now desktop browsers that can handle tel: links; Chrome's behavior on the desktop is, at worst, to do nothing when clicked. At best, you can make a call with Google Voice.
Because doing nothing when clicked is Chrome's fallback behavior, we should use that behavior as a fallback on all browsers.
If your page takes responsibility for creating tel: links, it should take responsibility for all tel: links and disable autodetection in the browser.
With all of this in mind, I suggest first adding a meta tag to your <head>:
<meta name="format-detection" content="telephone=no"/>
Then, define a JavaScript function that parses the UserAgent and returns true if and only if we think the browser will not bring us to an error page when the link is clicked:
function hasTelSupport()
{
return /Chrome\/|Mobile( Safari)?\/|Opera M(in|ob)i\/|w(eb)?OSBrowser\/|Mobile\;|Tablet\;/.test(navigator.userAgent);
}
Then, call that function from the onclick attribute in your link:
Call Me
This will allow tel: links to be clicked on Chrome, Edge, iOS Safari, Android Browser, Blackberry, Dorothy, Firefox Mobile, IE Mobile, Opera Mini, Opera Mobile, and webOS. The links will do nothing when clicked on other devices or browsers.
Please use international format for your tel: links. In other words, the first characters should be a + and a country code.
Thanks to TattyFromMelbourne's post I am now using a pretty simple bit:
My button id="call" will make the phone call based on his "probablyphone" test function but also will scroll down to the contact info section either way giving the button a working use no matter what.
I aslo replaced the alert with an empty function, to remove the pop-up.
<a id="call" href="#contact">PHONE US</a>
$("#call").on('click', function() {
var probablyPhone = ((/iphone|android|ie|blackberry|fennec/).test(navigator.userAgent.toLowerCase()) && 'ontouchstart' in document.documentElement);
var link = "callto:15555555555";
if ( !probablyPhone ) {
window.alert = function() {};}
else{window.location.href = link;}
});
</script>
You can use css3 media queries to detect a mobile window and hide the link accordingly.
#media(max-width:640px){
.your-calling-link{
display:none;
}
}
Alternately, if you want to show the link and just disable click functionality, use jquery function:
screen.width
or
screen.innerWidth
and disable the click functionality on the link using
$('.your-link').off(click);
One way of handling this is to create two separate divs and use display:hidden.
Example:
<div class="mobile-desktop"><p>123-456-7890</p></div>
<div class="mobile-mobile">123-456-7890</div>
In your css set your mobile break points. This part is really up to you. Let's say
#media only screen (min-width: 768px){
.mobile-mobile {
display:none;
}
}
#media only screen (max-width: 767px){
.mobile-desktop{
display:none;
}
}
This should let you hide one div based on screen size. Granted 789 is just a number I picked, so pick a size you believe is mobile. You can find them online at like this site I found on Google or others like it. Lastly, this is just a quick css markup, you might have to tinker but the idea is there.
This way works without adding any more CSS.
Try replacing the a tag with something else like a span tag, but only for mobile browsers of course. Benefits are that you are not cloaking this a with CSS preventing default action while keeping it still as a link. It won't be a anymore, so you won't have to worry.
I've created an example to here. Bold phone there works this way, see code below.
I took piece of code from one of the respondent to define if browser is mobile. And you have to mark these links with class="tel" or find a way to determine if the href has "tel:" in it. JQuery is also required.
// define if browser is mobile, usually I use Anthony's Hand mobile detection library, but here is simple detection for clarity
var probablyPhone = ((/iphone|android|ie|blackberry|fennec/).test(navigator.userAgent.toLowerCase()) && 'ontouchstart' in document.documentElement);
if ( !probablyPhone ) {
// find all the A with "tel:" in it, by class name
$('a.tel').each(function(){
var span = document.createElement('span');
// SPAN inherits properties of A, you can also add STYLE or TITLE or whatever
span.innerHTML = this.innerHTML;
span.className = this.className;
// replace A with SPAN
this.parentNode.insertBefore(span, this);
this.parentNode.removeChild(this);
});
}
Input this into custom css and call it a day:
a.tel { color: #FFFFFF; cursor: default; /* no hand pointer */ }
Change your color as needed.
Cheers!
I am adding the following css through javascript when mobile device is detected.
pointer-events:none
The js code is:
var a = document.getElementById("phone-number");
if (Platform.isMobile()) // my own mobile detection function
a.href = "tel:+1.212.555.1212";
else
$(a).css( "pointer-events", "none" );
In my target site, all phone link markups are in this pattern:
111-222-3333. My solution is such simple:
function setPhoneLink() {
if (screen.width > 640) {
$("a[href^='tel:']").each(function(){
$(this).replaceWith($(this).text());
});
}
}
Device-width: mobile<640; tablet >=768 and <1024; desk >=1024.
Source: http://javascriptkit.com/dhtmltutors/cssmediaqueries2.shtml
Don't use the screen size as a requirement for that.
You can use CSS media query like this:
#media (pointer: fine) { /* this is for devices using a mouse, maybe a pen */
a[href^="tel:"] { /* select only "tel:" links */
pointer-events: none; /* avoid clicks on this element */
}
}
#media (pointer: coarse) { /* this works for mobile phones */
}
More info: https://developer.mozilla.org/en-US/docs/Web/CSS/#media/pointer
#media screen {.telephone {pointer-events: none;}}