Before read please refer This post
This is example of while loop user extension using selenium IDE.
Make one file user-extension.js in C:/ drive.
Write code from this LINK
Now start Selenium IDE. add user-extension.js
Restart Selenium IDE.
Go to Source tab of selenium IDE. and paste HTML code in that. LINK
now come to Table tab of selenium tab and run this code. before start running slow speed of execution.
keep watching Log tab of selenium IDE.