求大神解决 为什么 JS 没用
<!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">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<head>
<title>欢迎来到丰丰网</title>
<style type="text/css">
td{
font-family: "新宋体"；font-size:14px;
}
</style>
<script type="text/javascript" src="st.JS">
</script>
<body>
<form name="myform" method="post" onsubmit="return check()"/>
<table width="556" height="173">
<tr>
<td height="31" colspan="3"><font size="+1" face="新宋体" color="#00009">丰丰邮箱</font></td>
</tr>
<tr>
<id widdth="129" height="33" aligan="right">丰丰邮箱：</id>
<td width="175">
<input type="text" name="mainMail" value="请输入邮件地址" onFocus="clso()" onblur="doAction0()"/>
</td>
<td width="236" id="td0">邮箱名只能是字母和数字、下划线</td>
</tr>
<tr>
<td height="32" align="right">密码：</td>
<td><input type="password" name="pwd" onblur="doAction1()"/></td>
<td id="td1">密码至少是6位数字</td>
</tr>
<tr>
<td height="36" align="right">再次输入密码：</td>
<td><input type="password" name="pwd"/></td>
<td>密码至少是6位数字</td>
</tr>
<tr>
<td colspan="36" align="center"><input type="submit" value="提交表单"\></td>
</tr>
</table>
</form>
</body>
<!-- <input type="button" name="点击" onclick="function_name()"> -->
</html>
alert("您好，欢迎你来到丰丰 世界");
var pass1,pass2;
var flag=false;
function clso()
{
var val=document.myform.mainMail.value;
if(val=="请输入邮件地址")
{
document.myform.mainMail.value="";
}
document.myform.mainMail.focus();
}
function doAction0()
{
var email=document.myform.mainMail.value;
var reg=/^[0-9a-zA-Z]+@[0-9a-zA-Z]+[\.]{1}[0-9a-zA-Z]+[\.]?[0-9a-zA-Z]+$/;
if(!reg.test(email))
{
document.getElementById("td0").innerHTML="<font color=red>邮件地址不符合条件</font>";
document.myform.mainMail.select();
flag=false;
}
else
{
document.getElementById("td0").innerHTML="<font color=green>邮件地址正确</font>";
flag=true;
}
}
function doAction1()
{
pass1=document.myform.pwd.value;
var reg1=/\d{6,}/;
if(!reg1.test(pass1))
{
document.getElementById("td1").innerHTML="<font color=red>密码不符合要求</font>";
flag=false;
}
else
{
document.getElementById("td1").innerHTML="<font color=green>密码符合要求</font>"；
flag=true;
}
}
function changeCode()
{
if(event.keyCode==13)
{
event.keyCode=9;
}
}
function check()
{
return flag;
}
document.onkeydown=changeCode;
