What could be the task of the statement debugger in the following JavaScript code?
function f(o)
{
if (o === undefined) debugger;
}
a) It does nothing but a simple breakpoint
b) It debugs the error in that statement and restarts the statement’s execution
c) It is used as a keyword that debugs the entire program at once
d) It is used to find error in the statement

Answer: a
Explanation: The debugger statement normally does nothing. If, however, a debugger program is available and is running, then an implementation may (but is not required to) perform some kind of debugging action. In practice, this statement acts like a breakpoint: execution of JavaScript code stops and you can use the debugger to print variable’s values.