javaScript验证代码(用户名,密码,邮箱)

<script language="javascript">

function IsDigit(cCheck)

{

return (('0'<=cCheck) && (cCheck<='9'));

}

function IsAlpha(cCheck)

{

return ((('a'<=cCheck) && (cCheck<='z')) || (('A'<=cCheck) && (cCheck<='Z')))

}

function IsaNull(cCheck)

{

return(cCheck != " ")

}

function checkform()

{

id = document.sform1.id.value;

if (id == "")

{

alert("请输入注册名");

document.sform1.id.focus();

return false;

}

for (nIndex=0; nIndex<id.length; nIndex++)

{

cCheck = id.charAt(nIndex);

if (!(IsDigit(cCheck) || IsAlpha(cCheck) || cCheck=='-' || cCheck=='_' || cCheck=='.'))

{

alert("用户名只能使用字母、数字以及-、_和.，并且不能使用中文");

document.sform1.id.focus();

return false;

}

}

chineseid = document.sform1.chineseid.value;

if (chineseid == "")

{

alert("请输入中文昵称");

document.sform1.chineseid.focus();

return false;

}

password = document.sform1.password.value;

if (password == "")

{

alert("请输入登陆密码");

document.sform1.password.focus();

return false;

}

password1 = document.sform1.password1.value;

if (password>password1)

{

alert("重复密码与登陆密码不相同");

document.sform1.password.focus();

document.sform1.password1.focus();

return false;

}

if (password<password1)

{

alert("重复密码与登陆密码不相同");

document.sform1.password.focus();

document.sform1.password1.focus();

return false;

}

if (document.sform1.email.value == "")

{

alert("请输入您的E-MAIL地址");

document.sform1.email.focus();

return false;

}

email=document.sform1.email.value;

emailerr=0

for (i=0; i<email.length; i++)

{

if ((email.charAt(i) == "@") & (email.length > 5))

{

emailerr=emailerr+1

}

}

if (emailerr != 1)

{

alert("请输入正确的E-MAIL地址");

document.sform1.email.focus();

return false;

}

if (document.sform1.checkask.value=="")

{

alert("密码提示问题不能为空");

document.sform1.checkask.focus();

return false;

}

if (document.sform1.checkans.value=="")

{

alert("您的密码提示问题答案不能为空");

document.sform1.checkans.focus();

return false;

}

return true;

}

< /script>