Is there any way to get the origin of an alert box?

Question

I work with some very large and confusing JavaScript files that I did not write. Sometimes an alert will come up but I don't know where it's coming from.

You could search all files for the text contained in the alert but if that text is dynamic it won't work.

Is there a way to set a breakpoint in order to intercept an alert?

Answer 1

At the very top of your HTML:

window.alert = function() {     debugger; } 

debugger is a statement that invokes any debugging functionality available. With developer tools open, you'll automatically hit a breakpoint whenever alert is called. You can then inspect the call stack to see exactly what called the custom alert function.

Answer 2

It may or may not be helpful to you, but you can overwrite the alert function to do whatever you want with it. For example, instead of alert boxes, you could have it log the message to the console.

window.alert = function(msg) {     console.log(msg); } alert('test');