Javascript Loops

Loops in javascript¶

Loops allow us to execute a set of statements repeatedly until the specified condition is met.

In javascript we have 2 types of loops

1. for loop
2. while loop

for loop syntax¶

for (intialization; condition; updation) {
  // code block to be executed
}

for loop example 1¶

for (var i = 0; i < 5; i++)
{
    console.log(i);
}

It will give below output

0 1 2 3 4

• In the above code we initialized i to 0 and checked condition i < 5 and updated i value by one in each iteration.
• Above iterates 5 times and executes the code and for the 6^th iteration the condition fails so, it stops the execution.

while loop syntax¶

JavaScript includes while loop to execute code repeatedly till it satisfies a specified condition. Unlike for loop, while loop only requires condition expression.

while(condition)
{
    /* code to be executed till the specified condition is true */
}

while loop example¶

var i =0;

while(i < 5)
{
    console.log(i);
    i++;
}

It will give below output

0 1 2 3 4

We use keyword break statement to stop the execution of the loop and continue to skip the iteration. Let's see a few examples.

for (var i = 0; i < 5; i++)
{
    if(i == 3){
        continue;
    }
    console.log(i);
}

It will give below output

0 1 2  4

for (var i = 0; i < 5; i++)
{
    if(i == 3){
        break;
    }
    console.log(i);
}

It will give below output

0 1 2

Let's see the same in while loop

var i =0;

while(i < 5)
{
    if(i == 3){
        break;
    }
    console.log(i);
    i++;
}

It will give below output

0 1 2

var i =0;

while(i < 5)
{
    if(i == 3){
        continue;
    }
    console.log(i);
    i++;
}

It will give below output

0 1 2 4