can I link JavaScript with PHP and how??

Answer 1

use jquery
ajax to send and load data

Answer 2

you can have PHP echoing javaScript like this:
<?php
$myName = "seamiki";
echo '<script>
alert("Hello '.$myName.'!!");
</script>';
?>

Answer 3

xss? when you echo get or post variable is xss attack

Answer 4

x s, s,