<!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=utf-8" />
<title>无标题文档</title>
</head>
<body>
用户名:<input type="text" name="name" id="name">
<input type="button" value="检测" id="check" οnclick="checkname()"/>
<!--
检测用户输入的是否是以字母数字下划线为开头,如果不是提示错误
-->
<script language="javascript" type="text/javascript">
function checkname(){
var name=document.getElementById("name").value;
//alert(name);
var parten=/^[a-zA-Z0-9_]/;
if(parten.test(name)){
alert("格式正确");
}else{
alert("输入错误,请重新输入");
}
}
</script>
</body>
</html>
<html xmlns=" http://www.w3.org/1999/xhtml ">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>
<body>
用户名:<input type="text" name="name" id="name">
<input type="button" value="检测" id="check" οnclick="checkname()"/>
<!--
检测用户输入的是否是以字母数字下划线为开头,如果不是提示错误
-->
<script language="javascript" type="text/javascript">
function checkname(){
var name=document.getElementById("name").value;
//alert(name);
var parten=/^[a-zA-Z0-9_]/;
if(parten.test(name)){
alert("格式正确");
}else{
alert("输入错误,请重新输入");
}
}
</script>
</body>
</html>