php - something wrong with replace string? -

ok can me this:

<?php $remove = $_get['hwid']; str_replace($_get['hwid']."<br />","",$str); ?> 

it doesnt delete text...

i know dont have set html file have thats because don't know how string...

let's have retrieved text (whether html or other form):

$str="the html file:  test  test1  test2  test3"; 

this function remove "test2" string:

$newstr=str_replace("test2","",$str); 

for more information of function take @ here

just 1 more thing, if have <br> after each line in example, need same too.