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How can I set multiple CSS styles in JavaScript?

Posted by: admin November 30, 2017 Leave a comment

Questions:

I have the following JavaScript variables:

var fontsize = "12px"
var left= "200px"
var top= "100px"

I know that I can set them to my element iteratively like this:

document.getElementById("myElement").style.top=top
document.getElementById("myElement").style.left=left

Is it possible to set them all together at once, something like this?

document.getElementById("myElement").style = allMyStyle 
Answers:

If you have the CSS values as string and there is no other CSS already set for the element (or you don’t care about overwriting), make use of the cssText property:

document.getElementById("myElement").style.cssText = cssString;

This is good in a sense as it avoids repainting the element every time you change a property (you change them all “at once” somehow).

On the other side, you would have to build the string first.

Questions:
Answers:

Using Object.assign:

Object.assign(yourelement.style,{fontsize:"12px",left:"200px",top:"100px"});

This also gives you ability to merge styles, instead of rewriting the CSS style.

You can also make a shortcut function:

const setStylesOnElement = function(styles, element){
    Object.assign(element.style, styles);
}

Questions:
Answers:

@Mircea: It is very much easy to set the multiple styles for an element in a single statement.
It doesn’t effect the existing properties and avoids the complexity of going for loops or plugins.

document.getElementById("demo").setAttribute(
   "style", "font-size: 100px; font-style: italic; color:#ff0000;");

BE CAREFUL: If, later on, you use this method to add or alter style properties, the previous properties set using ‘setAttribute’ will be erased.

Questions:
Answers:

Make a function to take care of it, and pass it parameters with the styles you want changed..

function setStyle( objId, propertyObject )
{
 var elem = document.getElementById(objId);
 for (var property in propertyObject)
    elem.style[property] = propertyObject[property];
}

and call it like this

setStyle('myElement', {'fontsize':'12px', 'left':'200px'});

for the values of the properties inside the propertyObject you can use variables..

Questions:
Answers:

A JavaScript library allows you to do these things very easily

jQuery

$('#myElement').css({
  font-size: '12px',
  left: '200px',
  top: '100px'
});

Object and a for-in-loop

Or, a much more elegant method is a basic object & for-loop

var el = document.getElementById('#myElement'),
    css = {
      font-size: '12px',
      left: '200px',
      top: '100px'
    };  

for(i in css){
   el.style[i] = css[i];
}

Questions:
Answers:

set multiple css style properties in Javascript

document.getElementById("yourElement").style.cssText = cssString;

or

document.getElementById("yourElement").setAttribute("style",cssString);

Example:

document
.getElementById("demo")
.style
.cssText = "margin-left:100px;background-color:red";

document
.getElementById("demo")
.setAttribute("style","margin-left:100px; background-color:red");

Questions:
Answers:

You can have individual classes in your css files and then assign the classname to your element

or you can loop through properties of styles as –

var css = { "font-size": "12px", "left": "200px", "top": "100px" };

for(var prop in css) {
  document.getElementById("myId").style[prop] = css[prop];
}

Questions:
Answers:

Don’t think it is possible as such.

But you could create an object out of the style definitions and just loop through them.

var allMyStyle = {
  fontsize: '12px',
  left: '200px',
  top: '100px'
};

for (i in allMyStyle)
  document.getElementById("myElement").style[i] = allMyStyle[i];

To develop further, make a function for it:

function setStyles(element, styles) {
  for (i in styles)
    element.style[i] = styles[i];
}

setStyles(document.getElementById("myElement"), allMyStyle);

Questions:
Answers:

Using plain Javascript, you can’t set all the styles at once; you need to use single lines for each of them.

However, you don’t have to repeat the document.getElementById(...).style. code over and over; create an object variable to reference it, and you’ll make your code much more readable:

var obj=document.getElementById("myElement").style;
obj.top=top;
obj.left=left;

…etc. Much easier to read than your example (and frankly, just as easy to read as the jQuery alternative).

(if Javascript had been designed properly, you could also have used the with keyword, but that’s best left alone, as it can cause some nasty namespace issues)

Questions:
Answers:

Your best bet may be to create a function that sets styles on your own:

var setStyle = function(p_elem, p_styles)
{
    var s;
    for (s in p_styles)
    {
        p_elem.style[s] = p_styles[s];
    }
}

setStyle(myDiv, {'color': '#F00', 'backgroundColor': '#000'});
setStyle(myDiv, {'color': mycolorvar, 'backgroundColor': mybgvar});

Note that you will still have to use the javascript-compatible property names (hence backgroundColor)

Questions:
Answers:

See for .. in

Example:

var myStyle = {};
myStyle.fontsize = "12px";
myStyle.left= "200px";
myStyle.top= "100px";
var elem = document.getElementById("myElement");
var elemStyle = elem.style;
for(var prop in myStyle) {
  elemStyle[prop] = myStyle[prop];
}

Questions:
Answers:

This is old thread, so I figured for anyone looking for a modern answer, I would suggest using Object.keys();

var myDiv = document.getElementById("myDiv");
var css = {
    "font-size": "14px",
    "color": "#447",
    "font-family": "Arial",
    "text-decoration": "underline"
};

function applyInlineStyles(obj) {
    var result = "";
    Object.keys(obj).forEach(function (prop) {
        result += prop + ": " + obj[prop] + "; ";
    });
    return result;
}

myDiv.style = applyInlineStyles(css);

Questions:
Answers:

I just stumbled in here and I don’t see why there is so much code required to achieve this.

Add your CSS code as a string.

let styles = 'color:red; font-size:15em; transform:rotate(20deg)';
document.querySelector('#styleMe').style = styles;
<div id=styleMe>a</div>

Questions:
Answers:

I created a JavaScript utility called styler.js which is quite easy to use on my blog. It makes getting and setting CSS styles incredibly easy.

Find it here: http://www.tjcafferkey.me/getting-setting-styles-javascript-styler/

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