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How to generate a html2canvas images with a hidden source (html) div

I am working in a project where I need to generate a profile picture of any member and its reviews, and some data, I started working with GDI, but it was so hard to understand, so I searched for other options and found Html2Canvas that works with javascript/jquery, everything is fine, the only thing I couldn't handle, and would like to know if there is a way to hide the source html div without breaking the result image.
Ex:
This is how is it now
This is how it should look
So, when I apply display:none on the css of the source div, the image result is like this:
And finally here is the code that I have so far
var div_to_hide = $("#mydiv:hidden");
$(function() {
$('span.stars').stars();
});
html2canvas([document.getElementById('mydiv')], {
onrendered: function (canvas) {
document.getElementById('canvas').appendChild(canvas);
var data = canvas.toDataURL('image/png');
var image = new Image();
image.src = data;
document.getElementById('image').appendChild(image);
}
});
$.fn.stars = function() {
return $(this).each(function() {
var val = parseFloat($(this).html());
val = Math.round(val * 4) / 4;
var size = Math.max(0, (Math.min(5, val))) * 16;
var $span = $('<span />').width(size);
$(this).html($span);
});
}
https://jsfiddle.net/ricardojriosr/6ap9Lx1f/8/
Now the question is how do I made this work showing only the image and not the HTML source. Thanks in advace.

Instead of trying to hide it before, hide (or remove) it after the canvas is rendered.
I'm not sure why var div_to_hide equals $("#mydiv:hidden"); but if you change it to var div_to_hide = $("#mydiv"); then, on line 12, after appending the image, you can run div_to_hide.hide();
And to avoid a flash of the HTML content, you can use some CSS trickery to cover up the original HTML. I made an example here, but you can adjust to fit whatever your actual needs are. https://jsfiddle.net/m5zq2kzn/

I had the same issue.
The solution that worked for me is a css trickery to position the div that I want to hide offscreen:
.offscreen {
position:absolute;
left:-10000px;
top:auto;
width:1px;
height:1px;
overflow:hidden;
}
Then use it like this:
html2canvas(document.getElementById("ticket_template"))
.then((canvas) => {
let imgData = canvas.toDataURL('image/png');
});

Edit iframe dynamic content

I'm trying to edit the size of dinamic content generated on external url.
There's my code:
HTML:
<div id="movie">
<iframe name="ifr" id="ifr" src="http://zeyu.ucoz.es/directvenvio.html" width="100%" height="480" frameborder="0" scrolling="no"></iframe>
</div>
In this source url, there are 2 scripts, that generate an iframe,
I'm trying to change the width and height of this line:
<script type='text/javascript'>
width=620,
height=382,
channel='zeyudirtc',
g='1';
</script>
This is what i'm trying:
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$('#ifr').ready(function(){
$('#ifr').contents().find('script').html('width=960, height=480, channel="zeyudirtc" ');
});
});
</script>
But this doesn't work.
Can help me please?
Thanks in advance.

If you have access to the iframes source, it is possible.
You will have to add Javascript Code to the iframe Content and the surrounding page.
The code you need inside the iframe Content should be like this:
First get the height, the iframe needs.
var height = getDocHeight();
var height = $("html").height();
var ua = window.navigator.userAgent;
var msie = ua.indexOf("MSIE ");
if(msie > 0){
height = Math.max(
document.documentElement["clientHeight"],
document.documentElement["scrollHeight"],
document.body["scrollHeight"]
);
}
Then you have to send a message to the surrounding page. Like this:
parent.postMessage(height, "DomainOfTheSurroundingPage");
That's it for the iframe.
On the other site you need to listen to the messages.
if (window.addEventListener) {
window.addEventListener ("message", receiveMessage, false);
} else {
if (window.attachEvent) {
window.attachEvent("onmessage", receiveMessage, false);
}
}
function receiveMessage(event)
{
var height = event.data;
do something();
}
Now you have the height (in px) to work with.
Wrap the iframe in a div.
Div
--- iframe
Then set the height of your wrapper div to 0 and the padding bottom to the height you submitted.
That should do the trick.
If you cannot add the code to the iframe Content however you can't edit the height and width of the iframe dynamically.

Check css "!important" value. In css this is a "high level"
#ifr {
height: 1000px!important;
}
http://jsfiddle.net/mraranturnik/4vqhLdpq/

OK, this is not a problem script or iframe but movi url. In url you have player size. If you want change player size you mast do somthing this
var playerUrl = $('#ifr').contents().find('iframe').attr('src');
Next write RegExp for url and put new src value for iframe in file :)
Your solution change only iframe size not a player size

if-image-height JavaScript statement

I have a grid of several images on my website. Hovering on one of these images will display a label with a name and price. The problem is that some images have a smaller height, and then the label gets too close to the bottom. Now I'm trying to write a JS if-statement in order to decrease the margin-top of that label only if the image-height is less than 200px.
This is how my html looks like:
<div class="fw_preview_wrapper">
<img src="'.$row['imageURL'].'" alt="" class="fw_featured_image" id="product_image" width="540">
<span class="price_tag" id="price_tag"><span class="actual_price">€ '.$row['Price'].'</span>
As you can see, the image URL is variable and comes from a database via php. For the js function, I set id="product_image".
This is the CSS part:
span.price_tag {
top: 86%;
}
As you can see above, there is a margin top set to 86%. This very value needs to be changed to "80%" when an image has a height of less than 200px.
and finally, the JS part:
<script>
var img = document.getElementById('#product_image');
//or however you get a handle to the IMG
var width = img.clientWidth;
var height = img.clientHeight;
if(height < 200){
$("span.price_tag").css('top','80%');
}
</script>
It doesn't work. I would appreciate some help. Thanks in advance!

Don't use hash # within param for getElementById:
var img = document.getElementById('product_image');
However you're using jQuery too, seeing your code, why not do just like this:
var img = $('#product_image');
var width = img.width();
var height = img.height();
if(height < 200){
$("span.price_tag").css('top','80%');
}

in javascript you should be using:
var img = document.getElementById('product_image');
# is used in jquery like: var img = $("#product_image")

remove # from the element getting statement , we use # to specify id in Jquery and not in js
try this..
<script type="text/javascript">
var img = document.getElementById('product_image');
var width = img.clientWidth;
var height = img.clientHeight;
if(height < 200)
$("span.price_tag").css('top','80%');
</script>

How to make a function set css width with a JavaScript variable?

I have this code:
...<script>
function handleSize()
{
var setObjectSize=window.innerWidth - 600;
document.getElementById("spin").style.width=setObjectSize + "px";
document.getElementById("spin").style.height=setObjectSize + "px";
}
</script>
</head>
<body>
<section id="spin" onLoad="handleSize()">...
All I am trying to do is to create a function that will set the height and width of the element according to window size using a formula and make sure height and width are the same. I am very new to javascript (almost know nothing about it), so despite there being a ton of example of such questions, and me following them, I can't get this code to work. What am I doing wrong?

The problem that I'm seeing, is that the onload event for the section tag isn't firing. You should add your javascript as a self-executing anonymous function to the end of your body tag and this will work for you.
<body>
<section id="spin" style="border:5px solid black;"></section>
<script>
(function () {
var setWindowSize = window.innerWidth - 600;
document.getElementById("spin").style.width = setWindowSize + "px";
document.getElementById("spin").style.height = setWindowSize + "px";
})();
</script>
</body>
See Here for a demo: http://jsfiddle.net/T7DW6/

You should move onload to the body tag:
<body onLoad="handleSize()">
<section id="spin">...

I would suggest you to use jQuery, that is JavaScript library used world wide. So in order to develop it using jQuery you need to do next
function setElementSize(elId) {
var _w $(window); //to get instance of window
var _el $('#' + elId); //jquery to get instance of element
var _width = _w.width();
var _height = _w.height();
//set width=height
if(_height>_width)
{
_height = _width;
} else { _width = _height; }
_el.css({
width: _width,
height: _height
});
}
//this will execute script when document is loaded.
$(document).ready(function(){
setElementSize('spin');
});
Function above will set width and height of element to match window size. If height > width then it will use width as width & height otherwise it will use height.
I assume that you want to change this automatically if window is resized then do this
$(window).resize(function(){
setElementSize('spin');
});

The onload event occurs when an object has been loaded.
onload is most often used within the element to execute a script once a web page has completely loaded all content (including images, script files, CSS files, etc.).
onload is only Supported by the Following HTML Tags:
body, frame, frameset, iframe, img, input type="image", link, script, style
from here: event_onload
then a is may be not the best here (height and weight does not change anything, you should use a div.
In order to know, the one to use, please read this:
what-is-the-difference-between-section-and-div

I try your exam and it works fine. The only thing that i changed was the way that you call the function
function handleSize(){
var setWindowSize=window.innerWidth - 600;
document.getElementById("spin").style.width=setWindowSize + "px";
document.getElementById("spin").style.height=setWindowSize + "px";
}
window.onload = function () {
handleSize();
}
I think that onLoad="handleSize()" have to be onload="handleSize()" but don't use that way because it is not a good practise!

this works for me
<!DOCTYPE html>
<html>
<body>
<p id="demo">Click the button and watch it grow.</p>
<button id = "myButton" onclick="myFunction()">Try it</button>
<script>
function myFunction()
{
var w = window.innerWidth;
var h = window.innerHeight;
var x = document.getElementById("myButton");
x.style.width = w + "px";
x.style.height = h + "px";
}
</script>
</body>
</html>

How to get the object of Iframe at clientside(javascript) which placed inside Table in asp.net

I have iframe inside the column of <asp:table>. I want to get the object of an iframe in javascript. I tried like this in <body> section:
<script type="text/javascript">
function resizeIframe()
{
var height = document.documentElement.clientHeight;
height -= document.getElementById('frame').offsetTop;
height -= 20;
document.getElementById('frame').style.height = height + "px";
};
document.getElementById('frame').onload = resizeIframe;
window.onresize = resizeIframe;
</script>
But I'm getting error like "object expected or null".

Your document has probably not finished loading (so, #frame does not exist yet). To fix this, make sure that the frame already exists by adding the code after the frame (or at the end of the document):
<iframe .../> ...
<script>
document.getElementById('frame').onload = resizeIframe;
window.onresize = resizeIframe;
</script>