Trigger breakpoint in Javascript

To trigger breakpoint in Javascript, you can add a 'debugger' in your code. For example:

function testing() {
    alert(123);
    debugger;
    alert(456);
}

The debugger will be triggered at runtime.

Debug mode in Eclipse and Tomcat

For Tomcat:
  set JPDA_ADDRESS=8000
  set JPDA_TRANSPORT=dt_socket
  catalina.bat jpda start

For Eclipse:
  Set Connection Port (8000) and Connection Host (localhost) in "Run > Debug Configurations"
  Configuration Type: "Remote Java Application"
  Set connection port to "8000"
  Set connection host to "localhost"