The break Statement

By Stephen Bucaro

The break statement provides you with a means of exiting a loop early. The break statement is commonly used to exit a loop when a value has reached or exceeded a set limit, or when searching through an array, when you've found the data for which you were searching.

The example below increments the variable x each time through the loop. Within the loop is an if statement that tests if x is greater than 8, and if so, executes a break statement.

var x = 0;
while (x < 12)
{
  x++;
  if(x > 8) break;
}
alert("loop exited when x = " + x);

The example below searches the day array for the day name "Wednesday", and, upon finding it, executes a break statement to end the loop.

var day = new Array("Monday","Tuesday","Wednesday",
"Thursday","Friday","Saturday","Sunday");
var index = 0;
while(index < day.length)
{
  if(day[index] == "Wednesday") break;
  index++;
}
alert("Found " + day[index]);

  Remember if you code nested loops, a break statement in an inner loop will not cause program flow to also exit an outer loop.

var x = 0;
var y = 0;
while(y < 12)
{
  while (x < 3)
  {
    if(y > 3) break;
    x++;
  }
  y++;
}
alert("loop exited x = " + x + " y = " + y);

In the example above, the inner loop contains a break statement to cause it to exit when y is greater than 3, but it exits only the inner loop, the outer loop continues to increment y.