Probem using parameters of setElementAttribute in swat

I'm using swat editor and I want to write a word in a text box. Normaly we can do it using its id or name, mas I working with a text box without any of them. The code of the text box is:

the both classes are the same in the other textboxes. The only difference between textboxes is the data-bind but even trying using |Expression| and writing the different code, doesn't work. Do you have any idea how can I do this?

Thank you