Today I was working on one of my client site and was redesigning Thesis theme for him. Everything went fine when we developed the theme locally but when we went live on the site, on every page load it started giving me Ajax error pop up.
My initial assumption was issue might be with my own js code or slider plugin js code. I removed my slider code but it was still giving me error.
I tried adding codes one by one but no joy. Site was still giving me error. Here is a work around which worked for me and might work for you too. Most of the time Ajax error pop up come when you are missing and JS file, or your script might be conflicting.
In this case issue was with any existing WordPress Plugin and only solution was to disable the plugins one by one and enable them one by one.
This tricked worked for me and in my case “Where did they go from here” WordPress plugin was causing issue. Disabling this plugin resolved the issue and site was working fine.
I hope this solution might help you if your blog gives Ajax error pop up.