fast/css/getComputedStyle/getComputedStyle-transform.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html lang="en">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <title>Transform Origin</title>
  <style type="text/css" media="screen">
    .container {
      height: 100px;
      width: 200px;
      margin: 30px;
      outline: 1px solid black;
    }
    .box {
      height: 100%;
      width: 100%;
      padding: 5px;
      margin: 5px;
      border: 5px solid gray;
      background-color: green;
      -webkit-transform-origin: 20% 50%;
    }
    #results {
      margin-top: 150px;
    }
  </style>
  <script type="text/javascript" charset="utf-8">
    if (window.testRunner) {
      testRunner.dumpAsText();
      testRunner.waitUntilDone();
    }

    var gTests = [
      { 'transform' : 'translate(80px, 90px)',  'result' : 'matrix(1, 0, 0, 1, 80, 90)' },
      { 'transform' : 'translate(10px, 50%)',   'result' : 'matrix(1, 0, 0, 1, 10, 60)' },
      { 'transform' : 'scale(1.2, 0.8)',        'result' : 'matrix(1.2, 0, 0, 0.8, 0, 0)' },
      { 'transform' : 'skew(-0.7rad, 20deg)',   'result' : 'matrix(1, 0.36397, -0.842288, 1, 0, 0)' },
      { 'transform' : 'rotate(45deg)',          'result' : 'matrix(0.707107, 0.707107, -0.707107, 0.707107, 0, 0)' },
    ];

    function compareTransform(expected, computed)
    {
      var re = /^matrix\(([^,]+), ([^,]+), ([^,]+), ([^,]+), ([^,]+?)(?:px)?, ([^,]+?)(?:px)?\)$/;
      var parsedExpected = re.exec(expected);
      var parsedComputed = re.exec(computed);
      for(var i = 1; i < 7; i++) {
         // use +/- 0.05 to avoid problems with rounding
         if (!(Math.abs(parsedComputed[i] - parsedExpected[i]) < 0.05))
            return false;
      }
      return true;
    }
    
    function runTests()
    {
      var testBox = document.getElementById('test-box');
      var testSpan = document.getElementById('test-span');
      var resultsBox = document.getElementById('results');

      gTests.forEach(function(curTest) {
        // set one of our test transforms
        testBox.style.webkitTransform = curTest.transform;
        testSpan.style.webkitTransform = curTest.transform;
        // read back computed style
        var computedTransform = window.getComputedStyle(testBox).webkitTransform;
        var computedSpanTransform = window.getComputedStyle(testSpan).webkitTransform;
        // compare expected result to computed transformation matrix
        var success = compareTransform(curTest.result, computedTransform);
        var result;
        if (success)
          result = curTest.transform + ' expected <code>' + curTest.result + '</code> : PASS';
        else
          result = curTest.transform + ' expected <code>' + curTest.result + '</code>, got <code>' + computedTransform + '</code> : FAIL';
        resultsBox.innerHTML += result + '<br>';

        if (computedSpanTransform !== 'none') {
          result = curTest.transform + ' applied to a non-box element: ' + ' expected <code>none</code> got <code>' + computedSpanTransform + '</code> : FAIL';
          resultsBox.innerHTML += result + '<br>';
        }
      });
      
      if (window.testRunner)
        testRunner.notifyDone();
    }
  </script>
</head>
<body onload="runTests()">

  <div class="container">
    <div id="test-box" class="box"></div>
  </div>

  <span id="test-span" class="box"></span>

  <div id="results">
  </div>
</body>
</html>