判斷上傳文件是否是Excel文件

 <script language="javascript">
 function doCheck(varCurObj) {
  var varCurValue = varCurObj.value;
  var varSufType = varCurValue.substring(varCurValue.lastIndexOf(".") + 1, varCurValue.length);

  if (varCurValue.length == 0) {
   document.getElementById("btnTrue").style.display = "none";
   document.getElementById("btnFalse").style.display = "block";
  } else {
   if (varSufType.toLowerCase() != "xls") {
    document.getElementById("btnTrue").style.display = "none";
    document.getElementById("btnFalse").style.display = "block";
   } else {
    document.getElementById("btnTrue").style.display = "block";
    document.getElementById("btnFalse").style.display = "none";
   }
  }
 }
</script>

<input type="file" id="fleItem" name="fleItem" οnchange="doCheck(this);" contentEditable="false" style="width: 300px;">
<input type="button" id="btnTrue" value="True" style="display: none;">
<input type="button" id="btnFalse" value="False" style="display: none;">