JavaScript Break Statement Example

JavaScript Break Statement Example

In this tutorial, you will learn

  • The label statement
  • JavaScript break statement
  • Syntax of JavaScript break statement
  • Example 1: break statement with for loop
  • Example 2: Using break statement to exit nested loop

The label statement

In JavaScript, you can label a statement for later use.  

Syntax of the label statement:

label: statement;

The label can be any valid identifier.

Example 1: labels the loop using the mylblabel.

mylb: for (let i = 0; i < 5; i++) {
    console.log(i);
}

In below, we will take an example of a break statement with label. You can also reference the label by using the break or continue statement. And you can also use the label with javascript loop such as fordo-while, and while loop.

JavaScript break statement

As the name suggests, The javascript break statement breaks/stopped the execution in programs/scripts.

Syntax of JavaScript break statement

 break; 

Example 1: break statement with for loop

See the following example ofbreak statement with for loop:

<script>
    
    var i = 1;
    for (i; i < 10; i++) {
        if (i % 5 == 0) {
            break;
        }
    }

   document.write(i + "<br>")

</script>  

The output of the script shown below:

5

How it works:

  • First, declare a variable  iand initialize it to 1.
  • Next, specified test condition.
  • After that, Increase the value of i by 1 in each iteration of the loop.
  • Use if statement with break.
  • Next, print the value of i.

In this above example, the for loop increments the variable i from 1 to 10. In the body of the loop, the if statement checks if i is variable divisible by 5 in each iteration of the loop. If so, the break statement is executed and the loop is terminated.

The control is passed to the next statement outside the loop that outputs the variable i to the console window.

Example 2: Using break statement to exit nested loop

As mentioned above, you use the break statement to terminate a label statement and transfer control to the next statement following the terminated statement. 

The syntax is as follows:

break label;

The break statement is typically used to exit the nested loop. See the following example.

<script>

    let iterations = 0; 
    top: for (let i = 0; i < 4; i++) { 
            for (let j = 0; j < 4; j++) { 
                iterations++; 
                if (i === 2 &amp;&amp; j === 2) { 
                    break top; 
                } 
            } 
        } 

    document.write(iterations + "<br>")

</script>  

The output of the script shown below:

11

Here,

  • First, the variable iterations is set to zero.
  • Second, both loops increase the variable i and j from 1 to 4.  In the inner loop, we increase the iteration variable and use an if statement to check both i and j equal 2. If so, the break statement terminates both loops and passes the control over the next statement following the loop.

Conclusion

In this tutorial, you have learned what is break statement and how to use the JavaScript break statement to control the code execution of for loop and nested loop.

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