สอบถามเรื่องการโยนค่าแบบโพสด้วย Ajax แต่เปรียบเทียบด้วย == ไม่ได้

function checkPasswordMatch(){
	var	status; 
	$.ajax({
      type: "POST",
	  async: false,
      url:"employees/checker.php",
      data: {passWord:$("#passWord").val(),SampPass:$("#samePassWord").val(),mod:"checkPass"} 
      }).done(function( data ) {
		if(data == "success"){
			status = true;
			$("#empInput7").removeClass( "has-error" );
			$("#samePassWord_error").text("");			
		 }else{
			status = false;
			$("#empInput7").addClass( "has-error" );
			$("#samePassWord_error").text("รหััสผ่านไม่ตรงกัน กรุณาตรวจสอบใหม่");
			$("#samePassWord_error").html(data);
		 }
	});
	//alert(status);
	return status;
}

<?php
include "../control.php";
$userName = trim($_POST["userName"]);
$passWord = trim($_POST["passWord"]);
$repass = trim($_POST["SampPass"]);
$mod = trim($_POST["mod"]);


/*echo "userNamue is : ".$userName."<br>";
echo "pass is : ".$passWord."<br>";
echo "re is : ".$repass."<br>";
echo "MOd is : ".$mod."<br>";
*/


if($mod == "checkPass"){
	if($passWord != $repass){
		echo "error";
	}else{
	echo "success";
/*	var_dump($passWord)."<br>";
	var_dump($repass)."<br>";*/
	}
}else{
	$query = $db->query("SELECT * FROM employee WHERE username = '".$userName."'");
	$row = $db->rows($query);
	if($row > 0){
		echo "error";
	}else{
		echo "success";
			//var_dump($query)."<br>";
		
	}
}
?>