Email address validation using Javascript - PHP Scripts, CSS

In forms when using email ID fields it is a good idea to use client side validation along with your programming language validation. The following example shows how you can validate an email address for a form. The script is cross browser compatibe (works for all browsers).

<script language = "Javascript">

function emailcheck(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 (emailcheck(emailID.value)==false){
emailID.value=""
emailID.focus()
return false
}
return true
}
</script>

<form name="frmSample" method="post" action="#" onSubmit="return ValidateForm()">
<p>Enter an Email Address :<input type="text" name="txtEmail"></p>
<p><input type="submit" name="Submit" value="Submit"></p>
</form>


Tags:

javascript textbox validation ,javascript email validation ,javascript numeric validation, javascript number validation,javascript date validation, javascript field validation, javascript validation, library javascript code validation