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HTML 

              
                <!DOCTYPE html>

<!-- 
Technique for maintaining the media queries in CSS only. Media query CSS execution is detected by JavaScript that reads the CSS generated content value.

  Credits: 
  http://adactio.com/journal/5414/
  http://adactio.com/journal/5429/
  https://gist.github.com/2481019
  https://gist.github.com/2482049
  https://css-tricks.com/examples/ConditionalCSS/

  Author: Aki Karkkainen (putting this demo together from the resources above)
  URL: https://gist.github.com/2944398
  Twitter: https://twitter.com/akikoo
-->

<html lang="en" dir="ltr">
  <head>
    <meta charset="utf-8" />
    <title>Detecting from JavaScript whether media queries have been executed in CSS</title>

  <!-- Mobile viewport optimization https://goo.gl/b9SaQ -->
  <meta name="HandheldFriendly" content="True">
  <meta name="MobileOptimized" content="320"/>
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  </head>
<body>

<h1>Conditional Content based on CSS Media Queries</h1>

<p>The media queries are maintained <strong>only</strong> in the CSS. Width check happens on resize event, you might want to remove that and trigger the script on page reload only.</p>

<p>
  <span class="mediaquery mediaquery-0">Width is 0&ndash;480px.</span> 
  <span class="mediaquery mediaquery-1">Width is 480&ndash;768px.</span> 
  <span class="mediaquery mediaquery-2">Width is more than 768px.</span>
</p>

</body>
</html>
!

CSS 

              
                @import "compass/css3";

body:after { /* Mobile first, no media query here */
  content: "nolayout";
  display: none; 
}

/* Demo start */
.mediaquery {
  display: none;
}

.mediaquery-0 {
  display: inline;
  color: red;
}/* Demo end */


@media only screen and (min-width: 30em) { /* 480px */
  body:after {
    content: "mobile";
  }

  /* Demo start */
  .mediaquery {
    display: none;
  }
    
  .mediaquery-1 {
    display: inline;
    color: blue;
  }/* Demo end */
}


@media only screen and (min-width: 48em) { /* 768px */
  body:after {
    content: "widescreen";
  }
  
  /* Demo start */
  .mediaquery {
    display: none;
  }
    
  .mediaquery-2 {
    display: inline;
    color: green;
  }/* Demo end */
}
!

JS 

              
                (function($, win, doc) {

  'use strict';

  $(window).resize(function() {

    var size = win.getComputedStyle(doc.body, ':after').getPropertyValue('content');

    // Some browsers have quotes, some don't in the returned value
    size = size.replace(/"/g, "");
    size = size.replace(/'/g, "");

    // If you want to open your console to see the current value
    // console.log('Current width is: ' + size);

    if (size === 'mobile') {
      // More code here, maybe loading content with Ajax
    }

    if (size === 'widescreen') {
      // More code here, maybe loading even more content?
    }

  }).resize();

}(jQuery, this, document));
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999px

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