javascript - Setting the style.maxWidth from a variable - Stack Overflow

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My cod is this:

<img src="img.png">

<dd id="123">COMMENT</dd>

<script>
var img = new Image();
img.onload = function () {
alert(this.width);
}
img.src = 'img.png';
</script>

This alerts a window with width of an img.png. The question is: how to set this width value for an element I need.

Something like:

document.getElementById('123').style.maxWidth = this.width;

Instead of:

alert(this.width);

My cod is this:

<img src="img.png">

<dd id="123">COMMENT</dd>

<script>
var img = new Image();
img.onload = function () {
alert(this.width);
}
img.src = 'img.png';
</script>

This alerts a window with width of an img.png. The question is: how to set this width value for an element I need.

Something like:

document.getElementById('123').style.maxWidth = this.width;

Instead of:

alert(this.width);

• javascript
• css
• variables

Share Improve this question Follow edited Jan 7, 2016 at 15:34 Will Vousden 33.4k99 gold badges8888 silver badges9797 bronze badges asked Jan 7, 2016 at 15:32 ХомичусХомичус 3322 silver badges88 bronze badges 1

• 2 document.getElementById('123').style.maxWidth = this.width; So what happened when you tried that? – Frédéric Hamidi Commented Jan 7, 2016 at 15:33

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 3

The width DOM property of an image is going to be a number.

The CSS max-width property only accepts a length as its value.

You need to add units to your number.

= this.width + "px";

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