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.
More Java Script Code: • Java Script Strings • Java Script Arithmetic Operators • The if/else Structure • Java Script confirm Message Box • Java Script Quick Reference : JavaScript toString Method Converts a Number to a String • Search and Replace Strings • Java Script Data Types • Determine Minimum and Maximum • The do/while Loop • Java Script alert Message Box
|