title: ASP.NET implementing a search box like stackoverflow search box
body: <p>I use VS2010,C# to develop an ASP.NET web app, I'm going to implement a search box like the one used in Stackoverflow (or other sites), initially there is a phrase (for instance "search") in the search text box, when user click in text box, its text is emptied and user can type his phrase, but if he leaves the text box (lost focus) empty, again the phrase "search" is displayed, how can I implement this nice effect?</p>
  
  <p>thanks</p>