相册程序中的表单检查

<script language="JavaScript" type="text/javascript">
<!--
function checkForm(){
    var filename=document.getElementById("photos").value;
    if(filename==""){
        alert("请先选择要上传的照片后再确定上传！");
        return false;
    }else{
        if(!IsImageName(filename)){
            alert("只允许上传jpg、jpeg、png形式的图片!");
            return false;
        }
    }
    return true;
}
function IsImageName(filename){
    var regex=/^.*(\\|\/)[^\.]+.(jpg|png|jpeg)$/
    var splitted=filename.match(regex);
    if(splitted==null)
        return false;
    return true;
}
//-->
</script>

 

<form action="../servlet/PhotoUpload" method="post" enctype="multipart/form-data" name="form1" id="form1" onsubmit="return checkForm();">
  <table width="67%" border="0" cellspacing="0" cellpadding="0">
    <tr>
      <td>选择文件</td>
      <td><input type="file" name="photos" id="photos" /></td>
    </tr>
    <tr>
      <td valign="top">照片说明</td>
      <td><textarea name="description" id="description" cols="36" rows="3"></textarea></td>
    </tr>
    <tr>
      <td colspan="2"><center>
        <input name="btnSubmit" type="submit" id="btnSubmit" value="上传" />
      </center>
      </td>
      </tr>
  </table>
  </form>