Chrome debugger inject javascript

I have this curiosity,

Is it, in some way, possible to inject javascript in my page and execute it and debug it? As you do with the console, but in the console you can't pause and watch variables.

Is it possible 开发者_StackOverflowto debug code that i put through console? Why isn't it possible to debug code received via XHR?

Thanks!

---

One trick I learned today from Chromium is that if you place the word:

debugger;

Right before the statement you want to debug. It will break on the debugger. It is really useful for injected scripts.

---

yes, its possible to include the javascript function in our webpage by using

window.onload = function fun(){alert("test");}

with in this event u can give a statement or any function.