PHP form validation problem?

I'm making one form using php, so validation is using PHP too,
I m posting the value in the same form and then trying to insert into mysql..look below.. I encountered the problem
--------------------------------------…

Name : 
Contact : 



  


" . "alert('Enter your name')" . "";
echo "";
}
else if($_POST["t2"] == "")
{
$err = "Enter Your Contact Number";
echo "";
}

echo " $err";
}

?>

--------------------------------------…

now what problem m facing here when i click on the "Submit" button i m getting the Error messages but the page is redirecting the i have to write all values all over again ..

suppose i have already wrriten a "NAME(t1)" but didnt write a CONTACT NUMBER(t2) PHP Validation then after m clicking on the SUBMIT button when i do this my page redirecting, m getting the second error "write your contact number" but i have to write all the values like NAME etc all over again ..

so my page is returning to true .. not false .

do you know how to set "return false" through php just like we do using javascript .. i cant use javascript for this .. have to use php in this .. plz help me ..

thank you ..