how to get the css keys and values for any html tag - audio

I would like to dump all css key/value pairs for an html tag.
In particular, I would like to learn the css properties for <audio> tag, so I can try to customize the look.
document.getElementById('myaudio').style returns a CSSStyleDeclaration object but length returns 0 and I cannot figure out to iterate over the key/value pairs.
Thank you


Try Firebug for firefox. It allows you to view the CSS and properties of any element on a webpage and allows in-page editing so you can customise it on the fly until you are happy without having to create hard and fast changes


You can't iterate over the keys in the style object. It's simply impossible.
The best answer is what Chris said. Use Firebug in Firefox, or similar tools in the other browsers, which can do the work for you and tell you exactly what CSS properties apply to the element.
(Make sure that you tell the tool to show you "user agent styles", not just styles you've added, so you can see what styles the browser applies automatically.)

Related

How to find xpath of js rendered element for puppeteer

Im trying to interact with a js rendered page. Essentially this is a free widget from tradingview; however, the color of the lines is not something I can change. (yes there is an override, however, it only affects 1 line) I need to be able to change 2 lines.
Trading View Advanced Chart Widget Constructor
Can anyone tell me if this is possible with a puppeteer? How can I get XPath for an element which is generated by JS? View source and developer tools do not provide any xpaths to the elements.

In Chrome extensions, why use a background page with HTML?

I understand that the background page of a Chrome extension is never displayed. It makes sense to me that a background page should contain only scripts. In what situations would HTML markup ever be needed?
At https://developer.chrome.com/extensions/background_pages there is an example with an HTML background page, but I haven't been able to get it to work (perhaps because I am not sure what it should be doing).
Are there any examples of simple Chrome extensions which demonstrate how HTML markup can be useful in a background page?

Historical reasons
The background page is, technically, a whole separate document - except it's not rendered in an actual tab.
For simplicity's sake, perhaps, extensions started with requiring a full HTML page for the background page through the background_page manifest property. That was the only form.
But, as evidenced by your question, most of the time it's not clear what the page can actually be used for except for holding scripts. That made the entire thing being just a piece of boilerplate.
That's why when Chrome introduced "manifest_version": 2 in 2012 as a big facelift to extensions, they added an alternative format, background.scripts array. This will offload the boilerplate to Chrome, which will then create a background page document for you, succinctly called _generated_background_page.html.
Today, this is a preferred method, though background.page is still available.
Practical reasons
With all the above said, you still sometimes want to have actual elements in your background page's document.
<script> for dynamically adding scripts to the background page (as long as they conform to extension CSP).
Among other things, since you can't include external scripts through background.scripts array, you need to create a <script> element for those you whitelist for the purpose.
<canvas> for preparing image data for use elsewhere, for example in Browser Action icons.
<audio> for producing sounds.
<textarea> for (old-school) working with clipboard (don't actually do this).
<iframe> for embedding an external page into the background page, which can sometimes help extracting dynamic data.
..possibly more.
It's debatable which boilerplate is "better": creating the elements in advance as a document, or using document.createElement and its friends as needed.
In any case, a background page is always a page, whether provided by you or autogenerated by Chrome. You can use all the DOM functions you want.

My two cents:
Take Google Mail Checker as an example, it declares a canvas in background.html
<canvas id="canvas" width="19" height="19">
Then it could manipulate the canvas in background.js and call chrome.browserAction.setIcon({imageData: canvasContext.getImageData(...)}) to change the browser action icon.
I know we could dynamically create canvas via background.js, however when doing something involving DOM element, using html directly seems easier.

TinyMCE and SVG

I'm using the latest/current TinyMCE editor (<script type="text/javascript" src='https://cdn.tinymce.com/4/tinymce.min.js'></script>) and it doesn't seem capable of displaying <svg>. I have some HTML saved in a database which contains some <svg>. When loaded in TinyMCE, it doesn't display.
Is this a known issue (I've searched and haven't found much)? Any workarounds?

TinyMCE strips empty and invalid tags. You can solve it by
Adding '&nbsp' to each empty element:
svg.find('*').each(function() {
if (!$(this).html()) {
$(this).text(' ');
}
});
here svg is your jQuery wrapped svg element.
Extending the valid elements according to the svg element reference*
extended_valid_elements: "svg[*],defs[*],pattern[*],desc[*],metadata[*],g[*],mask[*],path[*],line[*],marker[*],rect[*],circle[*],ellipse[*],polygon[*],polyline[*],linearGradient[*],radialGradient[*],stop[*],image[*],view[*],text[*],textPath[*],title[*],tspan[*],glyph[*],symbol[*],switch[*],use[*]"
*Note I added only the elements relevant for my case.

I tried Koen's first suggestion and it worked for existing SVG content (I added this in the setup callback). However it still filtered the SVG tags out when pasting HTML into the source code editor and then confirming the dialog.
After digging a bit into TinyMCE's source code to see where those elements are actually removed (it's in the DomParser class) I found an undocumented editor setting for the Schema class that specifies tags that are allowed to be empty without being removed. The only annoying thing is that you can't use it to add to the existing list, you can only override it. So when setting it you have to list the tags it has in there by default as well. Use this in the settings that you provide to TinyMCE when initialising it:
// First the list of tags that it normally knows about by default:
non_empty_elements: "td,th,iframe,video,audio,object,script,pre,code,area,base,basefont,br,col,frame,hr,img,input,isindex,link,meta,param,embed,source,wbr,track"
// Now we add tags related to SVGs that it doesn't normally know about:
+ "svg,defs,pattern,desc,metadata,g,mask,path,line,marker,rect,circle,ellipse,polygon,polyline,linearGradient,radialGradient,stop,image,view,text,textPath,title,tspan,glyph,symbol,switch,use",
This way these SVG tags should never be filtered out because they are empty - as long as they are also valid in general, e.g. by setting the extended_valid_elements as Koen suggested above or by allowing all elements (not recommended as it leaves you vulnerable to XSS attacks):
extended_valid_elements: "*[*]"
Please note that this worked for my version 4.5.8 of TinyMCE. Since this setting is undocumented it might not work anymore in current or future versions. Also they might've adjusted the default list that I'm overriding here in later versions. Find nonEmptyElementsMap and shortEndedElementsMap in Schema.js in their source code to find the default list in your version (the two lists get combined) and note that in there the tags are separated by spaces but when you supply a list yourself the list is separated by commas (for whatever reason).

Seams to be TinyMCE that removes it because it is an empty tag: http://world.episerver.com/forum/developer-forum/-EPiServer-75-CMS/Thread-Container/2015/1/tinymce-and-svgs/
You might be able to use this inside the init:
extended_valid_elements : "svg[*]",
It works with other empty tags etc, but have never tried with SVG.
From the forum post I linked to:
ok,I did some debugging into TinyMCE and the problem seems to be that
the svg element is detected as being empty and therefor removed.
Unfortunatley there is no config way to change this behavior but there
are some workarounds.
Always have a name attibute for the svg element: <svg name="something"
Always have a data-mce attribute for the svg element: <svg data-mce-something="something"
Include some text content within the svg element: <svg> </svg> Using these techniques i could succesfully store
inline svg in an xhtml property

I made it work by adding all valid SVG elements to the extended_valid_elements property of the settings object while initializing TinyMCE, no other action was needed
For your convenience here's the full list of SVG elements I used
a[*],altGlyph[*],altGlyphDef[*],altGlyphItem[*],animate[*],animateMotion[*],animateTransform[*],circle[*],clipPath[*],color-profile[*],cursor[*],defs[*],desc[*],ellipse[*],feBlend[*],feColorMatrix[*],feComponentTransfer[*],feComposite[*],feConvolveMatrix[*],feDiffuseLighting[*],feDisplacementMap[*],feDistantLight[*],feFlood[*],feFuncA[*],feFuncB[*],feFuncG[*],feFuncR[*],feGaussianBlur[*],feImage[*],feMerge[*],feMergeNode[*],feMorphology[*],feOffset[*],fePointLight[*],feSpecularLighting[*],feSpotLight[*],feTile[*],feTurbulence[*],filter[*],font[*],font-face[*],font-face-format[*],font-face-name[*],font-face-src[*],font-face-uri[*],foreignObject[*],g[*],glyph[*],glyphRef[*],hkern[*],image[*],line[*],linearGradient[*],marker[*],mask[*],metadata[*],missing-glyph[*],mpath[*],path[*],pattern[*],polygon[*],polyline[*],radialGradient[*],rect[*],script[*],set[*],stop[*],style[*],svg[*],switch[*],symbol[*],text[*],textPath[*],title[*],tref[*],tspan[*],use[*],view[*],vkern[*],a[*],animate[*],animateMotion[*],animateTransform[*],circle[*],clipPath[*],defs[*],desc[*],discard[*],ellipse[*],feBlend[*],feColorMatrix[*],feComponentTransfer[*],feComposite[*],feConvolveMatrix[*],feDiffuseLighting[*],feDisplacementMap[*],feDistantLight[*],feDropShadow[*],feFlood[*],feFuncA[*],feFuncB[*],feFuncG[*],feFuncR[*],feGaussianBlur[*],feImage[*],feMerge[*],feMergeNode[*],feMorphology[*],feOffset[*],fePointLight[*],feSpecularLighting[*],feSpotLight[*],feTile[*],feTurbulence[*],filter[*],foreignObject[*],g[*],hatch[*],hatchpath[*],image[*],line[*],linearGradient[*],marker[*],mask[*],metadata[*],mpath[*],path[*],pattern[*],polygon[*],polyline[*],radialGradient[*],rect[*],script[*],set[*],stop[*],style[*],svg[*],switch[*],symbol[*],text[*],textPath[*],title[*],tspan[*],use[*],view[*],g[*],animate[*],animateColor[*],animateMotion[*],animateTransform[*],discard[*],mpath[*],set[*],circle[*],ellipse[*],line[*],polygon[*],polyline[*],rect[*],a[*],defs[*],g[*],marker[*],mask[*],missing-glyph[*],pattern[*],svg[*],switch[*],symbol[*],desc[*],metadata[*],title[*],feBlend[*],feColorMatrix[*],feComponentTransfer[*],feComposite[*],feConvolveMatrix[*],feDiffuseLighting[*],feDisplacementMap[*],feDropShadow[*],feFlood[*],feFuncA[*],feFuncB[*],feFuncG[*],feFuncR[*],feGaussianBlur[*],feImage[*],feMerge[*],feMergeNode[*],feMorphology[*],feOffset[*],feSpecularLighting[*],feTile[*],feTurbulence[*],font[*],font-face[*],font-face-format[*],font-face-name[*],font-face-src[*],font-face-uri[*],hkern[*],vkern[*],linearGradient[*],radialGradient[*],stop[*],circle[*],ellipse[*],image[*],line[*],path[*],polygon[*],polyline[*],rect[*],text[*],use[*],use[*],feDistantLight[*],fePointLight[*],feSpotLight[*],clipPath[*],defs[*],hatch[*],linearGradient[*],marker[*],mask[*],metadata[*],pattern[*],radialGradient[*],script[*],style[*],symbol[*],title[*],hatch[*],linearGradient[*],pattern[*],radialGradient[*],solidcolor[*],a[*],circle[*],ellipse[*],foreignObject[*],g[*],image[*],line[*],path[*],polygon[*],polyline[*],rect[*],svg[*],switch[*],symbol[*],text[*],textPath[*],tspan[*],use[*],g[*],circle[*],ellipse[*],line[*],path[*],polygon[*],polyline[*],rect[*],defs[*],g[*],svg[*],symbol[*],use[*],altGlyph[*],altGlyphDef[*],altGlyphItem[*],glyph[*],glyphRef[*],textPath[*],text[*],tref[*],tspan[*],altGlyph[*],textPath[*],tref[*],tspan[*],clipPath[*],cursor[*],filter[*],foreignObject[*],hatchpath[*],script[*],style[*],view[*],altGlyph[*],altGlyphDef[*],altGlyphItem[*],animateColor[*],cursor[*],font[*],font-face[*],font-face-format[*],font-face-name[*],font-face-src[*],font-face-uri[*],glyph[*],glyphRef[*],hkern[*],missing-glyph[*],tref[*],vkern[*]

Create a map with clickable provinces/states using SVG, HTML/CSS, ImageMap

I am trying to create an interactive map where users can click on different provinces in the map to get info specific to that province.
Example:
archived: http://www.todospelaeducacao.org.br/
archived: http://code.google.com/p/svg2imap/
So far I've only found solutions that have limited functionality. I've only really searched for this using an SVG file, but I would be open to other file types if it is possible.
If anyone knows of a fully functioning way to do this (jQuery plug-in, PHP script, vector images) or a tutorial on how to do it manually please do share.

jQuery plugin for decorating image maps (highlights, select areas, tooltips):
http://www.outsharked.com/imagemapster/
Disclosure: I wrote it.

Sounds like you want a simple imagemap, I'd recommend to not make it more complex than it needs to be. Here's an article on how to improve imagemaps with svg. It's very easy to do clickable regions in svg itself, just add some <a> elements around the shapes you want to have clickable.
A couple of options if you need something more advanced:
http://jqvmap.com/
http://jvectormap.com/
http://polymaps.org/

I think it's better to divide my answer to 2 parts:
A-Create everything from scratch (using SVG, JavaScript, and HTML5):
Create a new HTML5 page
Create a new SVG file, each clickable area (province) should be a separate SVG Polygon in your SVG file,
(I'm using Adobe Illustrator for creating SVG files but you can find many alternative software products too, for example Inkscape)
Add mouseover and click events to your polygons one by one
<polygon points="200,10 250,190 160,210" style="fill:lime;stroke:purple;stroke-width:1"
onmouseover="mouseOverHandler(evt)"
onclick="clickHandler(evt)" />
Add a handler for each event in your JavaScript code and add your desired code to the handler
function mouseOverHandler(evt) {};
function clickHandler(evt) {};
Add the SVG file to your HTML page (I prefer inline SVG but you can use linked SVG file too)
Upload the files to your server
B-Use a software like FLDraw Interactive Image Creator (only if you have a map image and want to make it interactive):
Create an empty project and choose your map image as your base image when creating the new project
Add a Polygon element (from the Shape menu) for each province
For each polygon double click it to open the Properties window where you can choose an event type for mouse-over and click,
also change the shape opacity to 0 to make it invisible
Save your project and Publish it to HTML5, FLDraw will create a new folder that contains all of the required files for your project that you can upload to your server.
Option (A) is very good if you are programmer or you have someone to create the required code and SVG file for you,
Option (B) is good if you don't want to hire someone or spend your own time for creating everything from scratch
You have some other options too, for example using HTML5 Canvas instead of SVG, but it's not very easy to create a Zoomable map using HTML5 Canvas,
maybe there are some other ways too that I'm not aware of.

Just in case anyone will search for it - I used it on several sites, always the customization and RD possibilities were a perfect fit for what I needed. Simple and it is free to use:
Clickable CSS Maps
One note for more scripts on a site: I had some annoying problems with getting to work a map (that worked as a graphic menu) in Drupal 7. There where many other script used, and after handling them, I got stuck with the map - it still didn't work, although the jquery.cssmap.js, CSS (both local) and the script in the where in the right place. Firebug showed me an error and I suddenly eureka - a simple oversight, I left the script code as it was in the example and there was a conflict. Just change the front function "$" to "jQuery" (or other handler) and it works perfect. :]
Here's what I ment (of course you can put it before instead of the ):
<script type="text/javascript">
jQuery(function($){
$('#map-country').cssMap({'size' : 810});
});
</script>

Go to SVG to Script
with your SVG the default output is the map in SVG
Code which adds events is also added but is easily identified and can be altered as required.

I have been using makeaclickablemap for my province maps for some time now and it turned out to be a really good fit.

I had the same requirements and finally this Map converter worked for me. It is the best plugin for any map generation.

Here is another image map plugin I wrote to enhance image maps: https://github.com/gestixi/pictarea
It makes it easy to highlight all the area and let you specify different styles depending on the state of the zone: normal, hover, active, disable.
You can also specify how many zones can be selected at the same time.

The following code may help you:
$("#svgEuropa [id='stallwanger.it.dev_shape_DEU']").on("click",function(){
alert($(this).attr("id"));
});
Source

You have quite a few options for this:
1 - If you can find an SVG file for the map you want, you can use something like RaphaelJS or SnapSVG to add click listeners for your states/regions, this solution is the most customizable...
2 - You can use dedicated tools such as clickablemapbuilder (free) or makeaclickablemap (i think free also).
[disclaimer] Im the author of clickablemapbuilder.com :)

<script type="text/javascript">
jQuery(function($){
$('#map-country').cssMap({'size' : 810});
});
</script>
strong text

Web accessibility and h1-h6 headings - must all content be under these tags?

At the top of many pages in our web application we have error messages and notifications, 'Save' and other buttons, and then our h1 tag with the content title. When making a web application accessible, is it ever acceptable to have content above the top-level structure tag like we do here?

As a screen reader user I don't like content above the main heading. Normally I navigate by headings so would miss the error message. A better solution is to output an h1 heading above the error message, then leave the rest of your headings in tact giving you two h1 headings.

Yes (you can put stuff above them). The H simply means Heading. It's a question of what the heading relates to I guess.
My only caveat is, H2 shouldn't really be above H1, and H3 Shouldn't be above H2. But I don't think it's an actual rule.Websites have menus, warning, notifications. It's acceptable to put them above the rest of your content. I don't see how it would affect accessibility as long as your content is ordered logically. Look at the page CSS turned off. Does it look logical? That's the most important part of accessibility.
Although some people do go that extra mile and have the menu as the last item in the markup and use CSS to bring it back to the top. Personally, I find that solution counter productive. The menu is still important, it belongs at the top of the page.

Yes, just consider it is in that order that the user will get the information. So, if you just did an operation it sounds like a good idea to get any message related to it as the first thing. If it is a notification that appears on any page unrelated to what you are doing, I wouldn't put it above, as it might be a little weird.
Also you can use a text browser that doesn't use styles, it should look like a document with appropriate headers.

Heading tags are used to indicate the hierarchy of the content below it. You should only have one h1 tag and it should be the first content to appear on your page (this is usually the name of the site). Also, you shouldn't skip heading tags when drilling down through different tiers of content.
In your case, you can still use CSS to position items above the h1 tag as long as it is in the correct order in the html.

I assume the elements above the heading are used by JavaScript. In that case, it's preferable if they are created by JavaScript, not included in the source of the page.
To return to your original question, it is probably best that they be at the foot of the page. However, if they are hidden using the CSS "display: none;" or "visibility: hidden;" properties then they will not be seen by most (perhaps all?) screenreaders or by many other assistive technologies, and so should not be an issue. I've written a fairly detailed explanation of why accessibility technology ignores such elements.
Of course if somebody disables CSS things are going to look pretty messy. If there is content on the page that can be used even when CSS and/or JavaScript are disabled, then putting those elements at the bottom of the page will at least make things less cluttered.

Resources