How to create pop for when click textbox asp.net c#?

I have bind the data table in repeater inside the repeater many textbox is available

now i want to show the text box value to pop up window 

ex:

c sharp corner forums

 in the above value is want to shown in text box because many textbox have more then values than text box length so it is hided. i give the multi line textbox also but if the multiline textbox  is expanded design is affected. so i want to display the value to pop up window.

How to do it?

 

 

But the script is shows only first textbox value another text box value is not shown when click the other textboxes