Javascript to parse query string variables from URL

Parse query string via javascript

<script>
  function getQueryVariable(variable) {
    var query = window.location.search.substring(1);
    var vars = query.split("&amp;");
    for (var i=0;i&lt;vars.length;i++) {
      var pair = vars[i].split("=");
      if (pair[0] == variable) {
      return pair[1];
    }
  }
  alert('Query Variable ' + variable + ' not found');
}
</script>

// To test, make a request to page.html?x=Hello

<script>
  alert( getQueryVariable(“x”) );
</script>

I couldn't get the first variable after the '?'
e.g.:
URL: http://127.0.0.1/video.html?play=file.mp4&testvar=12345

pair play=file.mp4 was undetectable
pair testvar=12345 was

so I used the following to include the '?'

var vars = query.split(/[?,&]+/);