passing textbox's ClientID to javascript

i have a gridview control which has a column whose edit item template is textbox. There is one more column with linkbutton "Edit" . When i click on this linkbutton textbox box shows off in the column mentioned before and also 2 other linkbuttons appear "Update" and "Cancel" in this column
When i click on the "Update" Linkbutton i need to validate the textbox control "txtName"
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