php - Get url as www.abcd.com?curr=USD -

i working on e-commerce website

have drop down of different currencies if user selects usd currency links in website should open www.abcd.com/aboutus.php?curr=usd

thanks

 <form action='www.abcd.com/aboutus.php' method='get'>  <select name="curr" id='test'>  <option value='usd'>usd</option>  <option value='euro'>euro</option>  </select>  <input type='submit' value='submit'>  </form> 

on pages put

 <? $curr = $_get['curr'];  ?> 

now on every link include

 abcd.com?curr=<? echo $curr ?>