JavaScript break Statement
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Definition and usage
The break statement exits a switch statement or loop (for, for...in, while, do...while).
When the break statement is used with a switch statement, it exits the switch block. This will stop executing more code and/or case tests within the block.
When the break statement is used within a loop, it breaks out of the loop and continues executing the code after the loop (if any).
The break statement can also be used with an optional label reference to "exit" any JavaScript code block (see the "More examples" section below).
Note:If a label is not referenced, the break statement can only be used within a loop or switch.
Example
In this example, we use the for loop in conjunction with the break statement.
Loop through a block of code, but exit the loop when the variable i equals "3":
var text = "" var i; for (i = 0; i < 5; i++) { if (i === 3) { break; } text += "The number is " + i + "<br>"; }
More TIY examples are available at the bottom of the page.
Syntax
break;
Use optional labels to reference:
break labelname;
Technical details
JavaScript version: | ECMAScript 1 |
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More examples
Example
In this example, we use the while loop in conjunction with the break statement.
Loop through a block of code, but exit the loop when the variable i equals "3":
var text = ""; var i = 0; while (i < 5) { text += "<br>The number is " + i; i++; if (i === 3) { break; } }
Example
Exit the switch block to ensure that only one case is executed:
var day; switch (new Date().getDay()) { case 0: day = "Sunday"; break; case 1: day = "Monday"; break; case 2: day = "Tuesday"; break; case 3: day = "Wednesday"; break; case 4: day = "Thursday"; break; case 5: day = "Friday"; break; case 6: day = "Saturday"; break; }
Example
Use a labeled break statement to "exit" a JavaScript code block:
var cars = ["BMW", "Volvo", "Saab", "Ford"]; var text = ""; list: { text += cars[0] + "<br>"; text += cars[1] + "<br>"; text += cars[2] + "<br>"; break list; text += cars[3] + "<br>"; }
Example
Use a labeled break statement to "exit" nested for loops with a label reference:
var text = ""; var i, j; Loop1: // The first for loop is marked as "Loop1" for (i = 0; i < 3; i++) { text += "<br>" + "i = " + i + ", j = "; Loop2: // The second for loop is marked as "Loop2" for (j = 0; j < 5; j++) { if (j === 2) { break Loop1; } document.getElementById("demo").innerHTML = text += j + " "; } }
browser support
statement | Chrome | IE | Firefox | Safari | Opera |
---|---|---|---|---|---|
break | support | support | support | support | support |
related pages
JavaScript Tutorial:JavaScript Break and Continue
JavaScript Tutorial:JavaScript For Loop
JavaScript Tutorial:JavaScript While Loop
JavaScript Tutorial:JavaScript Switch
JavaScript Reference Manual:JavaScript continue Statement
JavaScript Reference Manual:JavaScript for Statement
JavaScript Reference Manual:JavaScript while Statement
JavaScript Reference Manual:JavaScript switch Statement
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