Hello I'm trying getElementById to change text inside my html web page. below you can find my 1st attempt
<!DOCTYPE html>
<html>
<body>
<h2>Use JavaScript to Change Text</h2>
<p>This example writes "Hello JavaScript!" into an HTML element with id="demo":</p>
<p id="demo"></p>
<script>
var net = require('net');
var sleep = require('sleep');
var element = document.getElementById("demo");
element.innerHTML = "Hello JavaScript!";
</script>
This code doesn't work because I can see the:
Use JavaScript to Change Text
This example writes "Hello JavaScript!" into an HTML element with id="demo":
but the:
"Hello JavaScript!"
is missing.
Changing the positions of the vars at the beginning of the js script makes the code working:
<!DOCTYPE html>
<html>
<body>
<h2>Use JavaScript to Change Text</h2>
<p>This example writes "Hello JavaScript!" into an HTML element with id="demo":</p>
<p id="demo"></p>
<script>
var element = document.getElementById("demo");
element.innerHTML = "Hello JavaScript!";
var net = require('net');
var sleep = require('sleep');
</script>
Why? I need both sleep and net later on when I'll write other parts of the code but I need to manipulate again the "demo" html as well.
There is a problem with both lines. The require() function is not a client side function, recognized by the browser. Typically require() is used in server side NodeJS code, but there is a require.js library file that you can add...
var net = require('net');
var sleep = require('sleep');
Add this to your project:
http://requirejs.org/docs/release/2.2.0/minified/require.js
And take a look at this :
http://requirejs.org/docs/api.html
Source :
Javascript require() function giving ReferenceError: require is not defined
It seems likely that the lines with
var net = require('net');
var sleep = require('sleep');
are actually causing an error, which in turn causes the JS to stop evaluating, so that it doesn't hit the getElementById line. You can check this in you browser's developer tools, in the console.
Related
I'm using Cheerio and request with Node.js to do some basic web scraping, but can't seem to figure out how to access the data. The page loads via request and I'm able to console.log the page title using Cheerio, but when I get to the scripts it's a complex mess of objects.
In the body section of the page it looks like..
<body>
<script src="someUrl" script type="text/javascript" />
<script src="someUrl" script type="text/javascript" />
<script src="someUrl" script type="text/javascript" />
<script type="text/javascript">var months = [6,12,24,36,48,60]; var amounts = [5000,10000,15000,20000,25000]</script>
I'm trying to get to the variables in the last script to store them as variables in my node script for use, but I can't seem to access them, even as text.
When I try this in node, I get the page title followed by some huge object response in the console, not the variable text to parse. Suggestions?
$ = cheerio.load(body);
console.log($('title').text());
var text = $('script');
console.dir(text[3]);
You can parse those variables with regex but cheerio is a little messy:
var cheerio = require('cheerio')
var html = `
<body>
<script src="someUrl" type="text/javascript" />
<script src="someUrl" type="text/javascript" />
<script src="someUrl" type="text/javascript" />
<script type="text/javascript">var months = [6,12,24,36,48,60]; var amounts = [5000,10000,15000,20000,25000]</script>
</body>
`
var str, $ = cheerio.load(html, {xmlMode: true}); // xmlMode: true is a workaround for many cheerio bugs.
console.log(str = $('script:not([src])')[0].children[0].data) // no cleaner way to do this, cheerio?
// var months = [6,12,24,36,48,60]; var amounts = [5000,10000,15000,20000,25000]
var months = JSON.parse(str.match(/months = (\[.*?\])/)[1])
console.log(months)
// [ 6, 12, 24, 36, 48, 60 ]
var amounts = JSON.parse(str.match(/amounts = (\[.*?\])/)[1])
console.log(amounts)
// [ 5000, 10000, 15000, 20000, 25000 ]
servercode.js
var express = require('express');
var app = express();
app.get("/abc",function(req, res) {
res.send("Hello");
});
clientcode.html
<html>
<head>
<script type="text/javascript">
$.get("/abc", function(string) {
alert(string);
})
</script>
</head>
<body>
There is no as such body of this. Its just works. :)
</body>
</html>
I want to call the servercode.js script from my client. Both files are on the node server. So that I receive the alert Hello in my client.
Though my main aim is to call a function periodically that would be written in servercode.js file. But for the time being I am not even being able to receive the hello response from the server and my files are in firebase hosting.
I hope I am clear with my question.
Help me on this!! Thank you very much.
Following are the structure of my application
Inside prototype.js file i have following code:
(function(exports) {
exports.foo = function() {
return 'bar';
};
})((typeof process === 'undefined' || !process.versions) ? window.common = window.common || {} : exports);
app.js contains
var express = require('express'),app = express(),server = require('http').createServer(app),io = require('socket.io').listen(server),port = 3000,path = require('path');
var common = require('common/prototype');
console.log(common.foo());
// listening to port...
server.listen(port);
//Object to save clients data
var users = [];
app.use(express.static(path.join(__dirname, 'public')));
app.get('/', function (req, res) {
res.sendfile('/public/index.html');
});
index.html contains
<!doctype html>
<html lang="en">
<head>
<title>Socket.io Demo</title>
</head>
<body>
<script src="/socket.io/socket.io.js"></script>
<script src="/common/prototype.js"></script>
<script>
alert(window.common.foo()); //This line will gives me an error TypeError: window.common is undefined
</script>
</body>
</html>
Now i would like to print
Hello, I am bar from server and client as well.
Now i am able to print from server side using following line
var common = require('common/prototype');
console.log(common.foo());
But could not able to show alert on client side. could you please help me to find the root cause for the issue.
The root cause is that when you do <script src="/common/prototype.js"></script> in your HTML the file won't be fetched because the Express static middleware is only looking for files under your public folder.
A quick way to test this is to copy your prototype.js to your javascript folder inside public. Then update your script tag to reference the file as follows <script src="/javascripts/prototype.js"></script>
The thing to remember is that the JavaScript files that live under node_modules are not automatically available to the browser.
I'm trying to connect the browser to my application via socket.io.
<script type="text/javascript" src="http://localhost:4000/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost:4000');
</script>
With this standard method all works fine.
Now I'm trying to transform this connection in "dynamic" based on the IP of the server, something like this:
<html>
<head>
var socket;
function loadFile(filename){
var ip_server = location.host;
var body = document.getElementsByTagName( 'body' )[0],
fileref = document.createElement('script');
fileref.setAttribute("type","text/javascript");
fileref.setAttribute("src", "http://"+ip_server+"/"+filename);
body.appendChild( fileref );
}
</head>
<body>
<script type="text/javascript">
loadFile("socket.io/socket.io.js");
socket = io.connect('http://'+location.host);
</script>
</body>
</html>
But firebug says ReferenceError: io is not defined on line socket = io.connect('http://'+location.host);.
How can I solve? There's a simple way to do what I'm thinking?
Thanks
Socket.io has "magical" integration with Node.js which means that something much simpler will work automatically:
<script src="/socket.io/socket.io.js"></script>
var socket = io.connect();
This will find the library and the socket with no explicit host or path. It should "just work."
const socket = io.connect(location.href);
Is there a way to change the Google Analytics code included in a template using Plates?
For example, for the below template:
<!DOCTYPE html>
<html>
<head></head>
<body>
<script id="googleAnalytics">
var _gaq=[['_setAccount','GA_ACCOUNT_CODE'],['_trackPageview']];
(function(d,t){var g=d.createElement(t),s=d.getElementsByTagName(t)[0];
g.src=('https:'==location.protocol?'//ssl':'//www')+'.google-analytics.com/ga.js';
s.parentNode.insertBefore(g,s)}(document,'script'));
</script>
</body>
</html>
I would like to use a different GA_ACCOUNT_CODE depending on the environment the code runs in.
Is this possible with Plates? If not, what is the common way one would solve this issue in NodeJS & Flatiron?
Plates' idea is great but far from complete. Here is a solution.
app.js
var fs = require('fs');
var plates = require('plates');
var flatiron = require('flatiron');
var app = flatiron.app;
app.use(flatiron.plugins.http);
app.router.get('/', function(){
var html = fs.readFileSync('index.html', 'utf-8');
var map = plates.Map();
var data = {"GA_ACCOUNT_CODE": "YOUR_CODE_FROM_CONFIG"}
map.where('data-ga').is('GA_ACCOUNT_CODE').insert('GA_ACCOUNT_CODE');
html = plates.bind(html, data, map);
this.res.html(html);
});
app.start(3000);
index.html
<!DOCTYPE html>
<html>
<head></head>
<body>
<script id="googleAnalytics" data-ga="GA_ACCOUNT_CODE">
var GA_ACCOUNT_CODE = document.getElementById('googleAnalytics').getAttribute('data-ga');
var _gaq=[['_setAccount',GA_ACCOUNT_CODE],['_trackPageview']];
(function(d,t){var g=d.createElement(t),s=d.getElementsByTagName(t)[0];
g.src=('https:'==location.protocol?'//ssl':'//www')+'.google-analytics.com/ga.js';
s.parentNode.insertBefore(g,s)}(document,'script'));
</script>
</body>
</html>
Another way would just be string.replace() like this:
var html = fs.readFileSync('index.html', 'utf-8');
html = html.replace('GA_ACCOUNT_CODE', 'YOUR_CODE_FROM_CONFIG');
this.res.html(html);
Have a look at cheerio for support. It's like any other css selector and dom manipulation frontend library, just backends.