jQuery Dialog Problem

jQuery Dialog Problem

Hello,
i have a very strange problem,

in my ASP.Net project, i use jquery 1.4.2, i have a Master Page that in it i have a ContentPlaceHolder like this:

<div id="content">
      <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
      </asp:ContentPlaceHolder>
</div>

i have a aspx page with the name of test.aspx, this page shows it's content by my ContentPlaceHolder in my Master Page. in my test.aspx i have a script tag that in it i have a simple alert script.

the problem is here, when i create a dialog for my div with the id of "content" in my Master Page, and run the page, my script in the test.aspx fires twice. this is very harmful when i want to run a script only once.

please help !!!