JavaScript verification Email (3 ways) _javascript Tips

Today for you to recommend three kinds of JavaScript verification email method, I hope to help you learn.
First: JavaScript Verify mailbox format

<script language=javascript runat=server>
function Isemail (stremail) {
if (Stremail.search (/^\w+ +)| (\.\w+)) *\@[a-za-z0-9]+ ((\.| -) [a-za-z0-9]+) *\. [a-za-z0-9]+$/)!=-1) return
true;
else
alert ("Oh");
}
</SCRIPT>
<input type=text onblur=isemail (this.value) >

Second: Use JavaScript to verify that email is correctly filled in

The third type: JS verification email

function Char_test (CHR)//character detection functions {var i; 
var smallch= "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; 
var bigch= "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; 
for (i=0;i<26;i++) if (Chr==smallch.charat (i) | | Chr==bigch.charat (i)) return (1); 
return (0); 
} function Spchar_test (CHR)//numeric and special character detection function {var i; 
var spch= "_-.0123456789"; 
for (i=0;i<13;i++) if (Chr==spch.charat (i)) return (1); 
return (0); 
function Email_test (str) {var i,flag=0; 
var at_symbol=0; 
Location of "@" detected var dot_symbol=0; “.” 
The detected position if (Char_test (Str.charat (0)) ==0) return (1); 
 The first character must be in the letter for (i=1;i<str.length;i++) if (Str.charat (i) = = ' @ ') {at_symbol=i; 
 Break 
}//Detect "@" position if (At_symbol==str.length-1 | | at_symbol==0) return (2); 
No mail server domain name if (at_symbol<3) return (3); 
The account number is less than three characters if (at_symbol>19) return (4); 
 Account number is more than 19 characters for (i=1;i<at_symbol;i++) if (Char_test (Str.charat (i)) ==0 && spchar_test (Str.charat (i)) ==0) 
return (5); for (i=at_symbol+1;i<str.length;i++) if (char_test Str.charaT (i)) ==0 && spchar_test (Str.charat (i)) ==0) return (5); 
Cannot use other special characters for (i=at_symbol+1;i<str.length;i++) if (Str.charat (i) = = '. ') dot_symbol=i; 
for (i=at_symbol+1;i<str.length;i++) if (dot_symbol==0 | | dot_symbol==str.length-1)//Simple detection has "." To determine whether the server name is legitimate 
 
return (6); 
return (0);
 Mail name Valid}

Above is the JavaScript authentication email method, everybody learns?