Dynamic DataTable in gridview

Question

Hi.....

I am creating a data table dynamically which has 10 rows and binding that table to Gridview.
 
 In Gridview, I am having 4 dropdownlist, 5 textbox and 1 label controls .

here i want to give clientside validations using javascript for textbox but I am unable to find the textbox control of a gridview using javascript.

please help..