谷歌Chrome不允许我放置断点

I've been using Google Chrome to debug my javascript, but then all of a sudden I can no longer place breakpoints. I click on the line number, where I previously clicked to add a breakpoint, but no breakpoint will be added. Sometimes if I click very fast, like a madman, I can see it trying to add breakpoints, but it won't stick.I've been using Google Chrome to debug my javas