JS判断文件是否存在

<script>
 function fileCheck() {
  var fso;
  fileFullPath = fileCtrl.value;
  fso = new ActiveXObject("Scripting.FileSystemObject");
  if (fso.FileExists(fileFullPath))

  else

 }
</script>

<input type="file" id="fileCtrl" contentEditable="false">

<input type="button" value="doFileCheck" onclick="fileCheck()">