How to open a file / browse dialog using javascript?

Use this.

<script>
  function openFileOption()
{
  document.getElementById("file1").click();
}
</script>
     <input type="file" id="file1" style="display:none">
     <a href="#" onclick="openFileOption();return;">open File Dialog</a>

Here is a non-jQuery solution. Note you can't just use .click() as some browsers do not support it.

<script type="text/javascript">
function performClick(elemId) {
   var elem = document.getElementById(elemId);
   if(elem && document.createEvent) {
      var evt = document.createEvent("MouseEvents");
      evt.initEvent("click", true, false);
      elem.dispatchEvent(evt);
   }
}
</script>
<a href="#" onclick="performClick('theFile');">Open file dialog</a>
<input type="file" id="theFile" />