Executing JavaScript using Firebug

1.From your Firebug program , then browse to the DOM pane (Document Object Model).
2. From your console page, go to the option “JavaScript Executor” located to the left of the red arrow.
3.Click on the arrow under the window for the JavaScript executor . This will display an executer for multiple lines.
4.Type in your command lines that you want to execute and press Enter.
5.Test you’re the JavaScript function and set some benchmarks by adding console.profile([yourtitle]) to the beginning of your JavaScript function and add console.profileEnd() to the end of your function
6.Go to the tab Script and choose a breakpoint from. From the left side,click the number to set your breakpoint. JavaScript will pause at a specific place to display the variable’s value.