Set CSS property in JavaScript?
Andrew Mclaughlin 
I've created the following...
var menu = document.createElement('select');How would I now set CSS attributes e.g width: 100px?
11 Answers
Use element.style:
var element = document.createElement('select');
element.style.width = "100px";Just set the style:
var menu = document.createElement("select");
menu.style.width = "100px";Or if you like, you can use jQuery:
$(menu).css("width", "100px");For most styles do this:
var obj = document.createElement('select');
obj.style.width= "100px";For styles that have hyphens in the name do this instead:
var obj = document.createElement('select');
obj.style["-webkit-background-size"] = "100px"That's actually quite simple with vanilla JavaScript:
menu.style.width = "100px";All of the answers tell you correctly how to do what you asked but I would advise using JavaScript to set a class on the element and style it by using CSS. That way you are keeping the correct separation between behaviour and style.
Imagine if you got a designer in to re-style the site... they should be able to work purely in CSS without having to work with your JavaScript.
In prototype I would do:
$(newElement).addClassName('blah')Just for people who want to do the same thing in 2018
You can assign a CSS custom property to your element (through CSS or JS) and change it:
Assigment through CSS:
element { --element-width: 300px; width: var(--element-width, 100%);
}Assignment through JS
ELEMENT.style.setProperty('--element-width', NEW_VALUE);Get property value through JS
ELEMENT.style.getPropertyValue('--element-width');Here useful links:
- *
When debugging, I like to be able to add a bunch of css attributes in one line:
menu.style.cssText = 'width: 100px';Getting used to this style you can add a bunch of css in one line like so:
menu.style.cssText = 'width: 100px; height: 100px; background: #afafaf';if you want to add a global property, you can use:
var styleEl = document.createElement('style'), styleSheet; document.head.appendChild(styleEl); styleSheet = styleEl.sheet; styleSheet.insertRule(".modal { position:absolute; bottom:auto; }", 0);<h1>Silence and Smile</h1>
<input type="button" value="Show Red" onclick="document.getElementById('h1').style.color='Red'"/>
<input type="button" value="Show Green" onclick="document.getElementById('h1').style.color='Green'"/><body> <h1>Silence and Smile</h1><br /> <h3>Silence and Smile</h3> <script type="text/javascript"> document.getElementById("h1").style.color = "Red"; document.getElementById("h1").style.background = "Green"; document.getElementById("h3").style.fontSize = "larger" ; document.getElementById("h3").style.fontFamily = "Arial"; </script>
</body>This works well with most CSS properties if there are no hyphens in them.
var element = document.createElement('select');
element.style.width = "100px";For properties with hyphens in them like max-width, you should convert the sausage-case to camelCase
var element = document.createElement('select');
element.style.maxWidth = "100px";
