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Loops In Javascript

A loop is concept of repeating until not false the condition. JavaScript has several loops with different conditions, these are following

loops

  1. for loop
  2. while loop
  3. do while
  4. for in

Basically you can use any loop in your program , but each has some conditions ;by the help of these you can understand its use .

Conditions

  • for loop is use for perfect time means you will know that how many time your loop need to run after that you will get its desired value for example: if you want to print 1-10 digits that means you need to run your loop ten times .
  • While loop is use, when you not know at which value you get your desired output
  • do while loop is same as while loop
  • for in loop use for array.

for loop syntax

for(initialvalue; condition;incrementinvalue)
{
//your code
}

 Example 

for(var i=0;i<=10;i++)
{
console.log(i);
}
  • it print digits from 0 to 10

While Loop Syntax

while(condition)
{
//your code
}

Example while loop

var bool=true;
while(bool){
console.log(bool);
bool=false;
}

do while Loop Syntax

do
{
//your code
}while(condition)

 Example

var bool=true;
do{
console.log(bool);
bool=false;
}while(bool)

for in loop syntax

for (variablename in object){
statement or block to execute
}

Example

var digit ={"A":1,"B":2,"C":3}
for (var i in digit) {
    console.log(  i+": "+digit[i]);
}
  •  Here i create a variable digit ,which is object and it has several properties
  • In loop i take the property name and i pass this in object index and it call that value .
for in loop not need any condition for complete the loop,because it work at the end of the property of object
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