Browser Zoom Check

HTML

<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">

<div>Current zoom level: <span id="zoom"></span></div>
<div>Device Pixel Aspect Ratio:<span id="device"></span></div>
<div>Zoom Level:<span id="level"></span>%</div>
<button type="button" class="btn btn-primary" id="reseteo" onclick="javascript:	window.document.body.style.zoom = 1.0;">Reset Zoom</button>


<div class="modal fade">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
        <h4 class="modal-title">Your Browser Zoom is <span id="levelM"></span>%</h4>
      </div>
      <div class="modal-body">
			<p>To view this program on the correct size please click the <b>Reset Zoom</b> button bellow to set the default browser size zoom level or <b>"click CTRL + 0"</b>.</p>
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-primary" id="reseteo" onclick="javascript:	window.document.body.style.zoom = 1.0;">Reset Zoom</button>
        <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
      </div>
    </div>
    <!-- /.modal-content -->
  </div>
  <!-- /.modal-dialog -->
</div>
<!-- /.modal -->

JavaScript

/* Detect-zoom
 * -----------
 * Cross Browser Zoom and Pixel Ratio Detector
 * Version 1.0.4 | Apr 1 2013
 * dual-licensed under the WTFPL and MIT license
 * Maintained by https://github/tombigel
 * Original developer https://github.com/yonran
 */

//AMD and CommonJS initialization copied from https://github.com/zohararad/audio5js
(function(root, ns, factory) {
  "use strict";

  if (typeof(module) !== 'undefined' && module.exports) { // CommonJS
    module.exports = factory(ns, root);
  } else if (typeof(define) === 'function' && define.amd) { // AMD
    define("detect-zoom", function() {
      return factory(ns, root);
    });
  } else {
    root[ns] = factory(ns, root);
  }

}(window, 'detectZoom', function() {

  /**
   * Use devicePixelRatio if supported by the browser
   * @return {Number}
   * @private
   */
  var devicePixelRatio = function() {
    return window.devicePixelRatio || 1;
  };

  /**
   * Fallback function to set default values
   * @return {Object}
   * @private
   */
  var fallback = function() {
    return {
      zoom: 1,
      devicePxPerCssPx: 1
    };
  };
  /**
   * IE 8 and 9: no trick needed!
   * TODO: Test on IE10 and Windows 8 RT
   * @return {Object}
   * @private
   **/
  var ie8 = function() {
    var zoom = Math.round((screen.deviceXDPI / screen.logicalXDPI) * 100) / 100;
    return {
      zoom: zoom,
      devicePxPerCssPx: zoom * devicePixelRatio()
    };
  };

  /**
   * For IE10 we need to change our technique again...
   * thanks https://github.com/stefanvanburen
   * @return {Object}
   * @private
   */
  var ie10 = function() {
    var zoom = Math.round((document.documentElement.offsetHeight / window.innerHeight) * 100) / 100;
    return {
      zoom: zoom,
      devicePxPerCssPx: zoom * devicePixelRatio()
    };
  };

  /**
   * For chrome
   *
   */
  var chrome = function() {
    var zoom = Math.round(((window.outerWidth) / window.innerWidth) * 100) / 100;
    return {
      zoom: zoom,
      devicePxPerCssPx:...