Change :hover CSS properties with JavaScript

Question

I need to find a way to change CSS :hover properties using JavaScript.

For example, suppose I have this HTML code:

<table>
  <tr>
    <td>Hover 1</td>
    <td>Hover 2</td>
  </tr>
</table>

And the following CSS code:

table td:hover {
background:#ff0000;
}

I would like to use JavaScript to change the <td> hover properties to, say, background:#00ff00. know I could access the style background property using JavaScript as:

document.getElementsByTagName("td").style.background="#00ff00";

But I don't know of a JavaScript equivalent for :hover. How do I change these <td>'s :hover background using JavaScript?

Your help is greatly appreciated!

Answer 1

I'd recommend to replace all :hover properties to :active when you detect that device supports touch. Just call this function when you do so as touch()

   function touch() {
      if ('ontouchstart' in document.documentElement) {
        for (var sheetI = document.styleSheets.length - 1; sheetI >= 0; sheetI--) {
          var sheet = document.styleSheets[sheetI];
          if (sheet.cssRules) {
            for (var ruleI = sheet.cssRules.length - 1; ruleI >= 0; ruleI--) {
              var rule = sheet.cssRules[ruleI];

              if (rule.selectorText) {
                rule.selectorText = rule.selectorText.replace(':hover', ':active');
              }
            }
          }
        }
      }
    }

Answer 2

Pseudo classes like :hover never refer to an element, but to any element that satisfies the conditions of the stylesheet rule. You need to edit the stylesheet rule, append a new rule, or add a new stylesheet that includes the new :hover rule.

var css = 'table td:hover{ background-color: #00ff00 }';
var style = document.createElement('style');

if (style.styleSheet) {
    style.styleSheet.cssText = css;
} else {
    style.appendChild(document.createTextNode(css));
}

document.getElementsByTagName('head')[0].appendChild(style);

Answer 3

What you can do is change the class of your object and define two classes with different hover properties. For example:

.stategood_enabled:hover  { background-color:green}
.stategood_enabled        { background-color:black}
.stategood_disabled:hover { background-color:red}
.stategood_disabled       { background-color:black}

And this I found on: Change an element's class with JavaScript

function changeClass(object,oldClass,newClass)
{
    // remove:
    //object.className = object.className.replace( /(?:^|\s)oldClass(?!\S)/g , '' );
    // replace:
    var regExp = new RegExp('(?:^|\\s)' + oldClass + '(?!\\S)', 'g');
    object.className = object.className.replace( regExp , newClass );
    // add
    //object.className += " "+newClass;
}

changeClass(myInput.submit,"stategood_disabled"," stategood_enabled");