title: php add variable to url without remove exiting
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/9666909/keeping-url-parameters-during-pagination">keeping url parameters during pagination</a>  </p>
  </blockquote>
  
  
  
  <p>Currently I've pagination that is passing a variable as <code>"?page=1"</code>. The url variable of <code>"?page=1"</code> is dynamically changed for instance <code>"?page=3"</code> and so on. The problem is, when I have a few action for my site, like as <code>"?action=show_post</code> or <code>?action=show_categories</code> and etc". So If I click my pagination number the variable <code>"?action=show_post"</code> will be removed from my url. </p>
  
  <p>My question is: How to add a variable to an <code>url</code> and will be like this <code>"?action=anything&amp;page=anything"</code> and "anything key just for term or parable and will change dynamically value"</p>