Help in JavaSCripts plz!! fast!!

hi.. i want to fix my JavaScript during the run in a dynamic way...
example:

i got 2 pages A and B


1) A have a link to B
2) page B got a JavaScript
3) the JavaScript of page B will be change (Optimized) depend what the user will inter data in Page A,

anyone can help???

How is it going to change? Please provide more information.

Also, change your title. Make it descriptive.

Cookie.

At least he said "plz" and not "TIA". ;)