The debugger statement can be placed anywhere in procedures to suspend execution. Using the debugger statement is similar to setting a breakpoint in the code. By definition such statement must absolutely be removed from the source code to prevent any unexpected behavior in production.
Here is an example of JavaScript code :
for (i = 1; i<5; i++) { // Print i to the Output window. Debug.write("loop index is " + i); // Wait for user to resume. debugger; }