There is a bad problem with JS in the page

Analysis: Previously useful but later not useful (modified the other code on this page)

Possible reasons: There are errors in the newly written code, resulting in the subsequent JS not working properly
Problem-solving: in Firebug, see the error in the console, and probably navigate to the location of the error code. The exact method can be used to search for the error statement.

For example: EdX Unbound course, JS does not work

<a href= "/courses_curriculum_list/" rel= "Leanmodal" id= "Make_group" > View schedule </a></span>

Simply remove rel= "Leanmodal" id= "Make_group"

There is a bad problem with JS in the page