How to run a javascript function periodically in iPad

Dear all,

I was found a problem in my web apps for iPad. I was wrote a function and using setTimeout function to run this function periodically. If I click on the textbox in my form, the build-in keyboard will come out and all the javascript executing function in the page are all stopped. After the key-in all the characters in the textbox, the javascript doesn't run anymore unless I triggered by hand but I need to run specific function all the time.

Does anyone know how to solve this problem?

Thanks!