email validation

[mren]

Hi all, I need from simple and effective code for email validation.

Thanks in advance

[BigJON]

This script check for a period "." character anywhere after the 3rd character in the string

function isValidEmail(str) {
   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
   }

If anyone knows a simple way, let it show.

[lnxpower]

There is no doubt use of JavaScript is the most successful method for email validation

<script language = "Javascript">
function echeck(str) {
        var at="@"
        var dot="."
        var lat=str.indexOf(at)
        var lstr=str.length
        var ldot=str.indexOf(dot)
        if (str.indexOf(at)==-1){
           alert("Invalid E-mail ID")
           return false
        }
        if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
           alert("Invalid E-mail ID")
           return false
        }
        if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
            alert("Invalid E-mail ID")
            return false
        }
         if (str.indexOf(at,(lat+1))!=-1){
            alert("Invalid E-mail ID")
            return false
         }
         if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
            alert("Invalid E-mail ID")
            return false
         }
         if (str.indexOf(dot,(lat+2))==-1){
            alert("Invalid E-mail ID")
            return false
         }
         if (str.indexOf(" ")!=-1){
            alert("Invalid E-mail ID")
            return false
         }
          return true                    
    }
function ValidateForm(){
    var emailID=document.frmSample.txtEmail
    if ((emailID.value==null)||(emailID.value=="")){
        alert("Please Enter your Email ID")
        emailID.focus()
        return false
    }
    if (echeck(emailID.value)==false){
        emailID.value=""
        emailID.focus()
        return false
    }
    return true
 }
</script>

Function echeck is used to verify if the given value is a possible valid email address. This function thus simply makes sure the email address has one (@), at least one (.). It also makes sure that there are no spaces, extra '@'s or a (.) just before or after the @. It also makes sure that there is at least one (.) after the @.
Function ValidateForm is used to make sure that the email field is not blank and that it is a valid email address on form submission.

[cech]

This code make 100% checking for properly typed email address:

function validate(form_id,email) {
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   var address = document.forms[form_id].elements[email].value;
   if(reg.test(address) == false) {
      alert('Invalid Email Address');
      return false;
   }
}

There is a simple form who call the function above:

<form id="form_id" method="post" action="action.php" onsubmit="javascript:return validate('form_id','email');">
   <input type="text" id="email" name="email" />
   <input type="submit" value="Submit" />
</form>