Revise HTML Input Form format

I used web crawler function download some webpages which contains some input from functions, likes:

<input type="text" name="LSTNAM" size="20" maxlength="35">
<input type="text" name="FSTNAM" size="20" maxlength="35">

Here I want to know whether I can use some JS method to find all the ""input type="text"", and revised these forms instead of just manually revise them one by one. Here is the target I want to achieve:

<input type="text" name="LSTNAM" size="20" maxlength="35"     onclick="shwinputtypetext(this);">
<input type="text" name="FSTNAM" size="20" maxlength="35" onclick="shwinputtypetext(this);">