[jQuery] Issue in finding the controls from asp.net usercontrols

Hi,

I am trying to find a table first <tr> tag which is located in a
usercontrol from a main page like the following

$("table[id*=nav]").find("tr").size()

this shows 0, but it is available on the "usercontrol"

i couldn't able to find any elements in usercontrol through main page.

please help.