title: How to check whether a certain asp.net text box exists in a page
body: <p>Suppose I have a master page where I have written some javascript to access the value of a particular asp.net text box, which resides in one of its content pages, but not in all the pages. This piece of javascript code can't be moved to that particular content page because of some restrictions.</p>
  
  <p>Now I need a way to determine whether or not that text box exists in the page, which will imply that the content page containing that text box has been loaded.</p>
  
  <p>How I can I do that in javascript?</p>