Hi All I am having this problem. Locally everything is working fine. Once I upload the published version on production the IDs of all elements will have a different prefix.
I know that the prefix is caused by using master pages, but why it is different from local to production?
See Image
alt text http://img.skitch.com/20100708-pg6exce3jd6f3dga2huse1u7pi.jpg
I agree with Matt-dot-net, dont use hardcoded client-side control ids.
However, check your dev/production web.configs for xhtmlConformance mode=”Legacy” (or something similar), if only one of your configs has this set then it may account for you having different ids on dev and production .
Cheers Tigger