Manipulate CSS Before Selector With JQuery

I'm trying to access the CSS :before and :after selectors with jQuery. I have tried a few methods, but it seems that the CSS selectors can't be seen by the DOM. What I'm trying to

Solution 1:

(function($) {
  jQuery.fn.extend({
    getPseudo: function(pseudo, prop) {
      var props = window.getComputedStyle(
        $(this.selector).get(0), pseudo
      ).getPropertyValue(prop);
      return String(props);
    },
    setPseudo: function(_pseudo, _prop, newprop) {
      var elem = $(this);
      var s = $("style");
      var p = elem.getPseudo(_pseudo, _prop);
      console.log(p)
      var r = p !== "" ? new RegExp(p) : false;
      var selector = $.map(elem, function(val, key) {
        return [val.tagName, val.id 
                ? "#" + val.id : null, val.className ? "." + val.className 
                : null]
      });
      var _setProp = "\n" + selector.join("")
        .concat(_pseudo)
        .concat("{")
        .concat(_prop + ":")
        .concat(newprop + "};");
      ((!!r ? r.test($(s).text()) : r) ? $(s).text(function(index, prop) {
        return prop.replace(r, newprop)
      }) : $(s).append(_setProp));
      return this
    }
  })
})(jQuery);

$(".className").setPseudo(":before", "background", "blue");

.className:before {
  background: red;
  content: "123";
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js">
</script>

<div class="className">abc</div>

Solution 2:

You can't change the style of pseudo elements with javascript, but you could add a <span> inside of your .className and then target that.

$('.className span').css('background-color', bgColor);