คลิกที่นี่ http://app.memo8.com/web/email-verification/

<script type="text/javascript" src="numberFormat154.js"></script>
<script type="text/javascript">
var num = new NumberFormat(10901.375).toFormatted();
// num will equal 10,901.38
</script>

Download : NumberFormat154.js

Code:Header

<script language="Javascript">

function validatefrm(){ 

 var theForm = document.form1;

 var emailRE = /^([a-zA-Z0-9_.-])+@(([a-zA-Z0-9-])+.)+([a-zA-Z0-9]{2,4})+$/;

 var errMsg = "";

 var setfocus = ""; 	if (theForm['textfield'].value != ""){

if (!emailRE.test(theForm['mail'].value)){

 		errMsg = "mail Fail!";

 		setfocus = "['mail']";

 	}

 }

 if (errMsg != ""){

 	alert(errMsg);

 	eval("theForm" + setfocus + ".focus()");

 }

 else theForm.submit();

}

</script>

Code:Body

<form action="" method="post" name="form1" onSubmit="validatefrm();return false;">

   <input type="text" name="mail">

   <input type="submit" name="Submit" value="Submit">

 </form>

Code:Header

<script language="Javascript"><!--

function validatefrm(){	var theForm = document.frmAdd;

 var errMsg = "";

 var setfocus = "";

if (theForm['Fname'].value == ""){

 	errMsg = "ชื่ออ่ะ";

 	setfocus = "['Fname']";

 }

 if (theForm['Lname'].value == ""){

 	errMsg = "นามสกุลอ่ะ";

 	setfocus = "['Lname']";

 }

if (errMsg != ""){

 	alert(errMsg);

 	eval("theForm" + setfocus + ".focus()");

 }

 else theForm.submit();

}

</script>

Code:Body

<form action="" method="post"  name="frmAdd" id="frmAdd" onSubmit="validatefrm();return false;">
Fname :<input name="Fname" type="text" id="Fname"><br />
Lname :<input name="Lname" type="text" id="Lname" >
<input name="Submit" type="submit">
</form>

code

function validateEmail($email){
 return eregi('^[a-zA-Z0-9._-]+@[a-zA-Z0-9._-]+\.([a-zA-Z]{2,4})$',$email);
}

Example

if(validateEmail("youmail@memo8.com")){

   echo"ถูกค้าบบบ";

}else{

   echo"ผิดว๊อยยย";

}

<SCRIPT LANGUAGE="JavaScript">

if((document.form1.upload.value.lastIndexOf(".jpg")==-1) {
alert("Please upload only .jpg extention file");
return false;
}

</SCRIPT>