js判断上传文件类型 格式 扩展名(后缀名)
<!doctype html public "-//w3c//dtd xhtml 1.0 transitional//en" "http://www.w3.org/tr/xhtml1/dtd/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html; charset=gb2312" />
<title>js代码</title>
<script language="网页特效">
function isvalidatefile(obj){
var extend = form1.file.value.substring(form1.file.value.lastindexof(".")+1);
if(extend==""){
}else{
if(!(extend=="xls"||extend=="doc")){
alert("请上传后缀名为xls或doc的文件!");
var nf = obj.clonenode(true);
nf.value='';
obj.parentnode.replacechild(nf, obj);
return false;
}
}
return true;
}
</script>
</head><body>
<form id="form1" name="form1" enctype="multipart/form-data" method="post" action="">
<label for="filefield"></label>
<input type="file" name="file" id="file" />
<input type="button" name="button" id="button" value="检测上传文件类型" onclick="isvalidatefile('file');" />
</form>
</body>
</html>