Interrupting Loops

When you work with loops, there are times when you need to interrupt the execution of code inside the code itself, without waiting for the next iteration. There are two different ways to do this: using the break and continue keywords.

The break keyword stops execution of a for or while loop completely. The continue keyword, on the other hand, stops execution of the code inside the loop and continues on with the next iteration. Consider the following examples.

This example shows using break if the day is Wednesday:

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var days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"];
for (var idx in days){
  if (days[idx] == "Wednesday")
    break;
  console.log("It's " + days[idx] + "<br>");
}

Once the value is Wednesday, loop execution stops completely:

It's Monday
It's Tuesday

This example shows using continue if the day is Wednesday:

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var days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"];
for (var idx in days){
  if (days[idx] == "Wednesday")
    continue;
  console.log("It's " + days[idx] + "<br>");
}

Notice that the write is not executed for Wednesday because of the continue statement, but the loop execution does complete:

It's Monday
It's Tuesday
It's Thursday
It's Friday