The JavaScript if-else statement is used to execute the code whether condition is true or false. There are three forms of if statement in JavaScript.
- If Statement
- If else statement
- if else if statement
JavaScript If statement
It evaluates the content only if expression is true. The signature of JavaScript if statement is given below.
if(expression){
//content to be evaluated
}Flowchart of JavaScript If statement
Let’s see the simple example of if statement in javascript.
<script>
var a=20;
if(a>10){
document.write("value of a is greater than 10");
}
</script>Output of the above example
value of a is greater than 10
JavaScript If…else Statement
It evaluates the content whether condition is true of false. The syntax of JavaScript if-else statement is given below.
if(expression){
//content to be evaluated if condition is true
}
else{
//content to be evaluated if condition is false
}Flowchart of JavaScript If…else statement
Let’s see the example of if-else statement in JavaScript to find out the even or odd number.
<script>
var a=20;
if(a%2==0){
document.write("a is even number");
}
else{
document.write("a is odd number");
}
</script>Output of the above example
a is even number
JavaScript If…else if statement
It evaluates the content only if expression is true from several expressions. The signature of JavaScript if else if statement is given below.
if(expression1){
//content to be evaluated if expression1 is true
}
else if(expression2){
//content to be evaluated if expression2 is true
}
else if(expression3){
//content to be evaluated if expression3 is true
}
else{
//content to be evaluated if no expression is true
}Let’s see the simple example of if else if statement in javascript.
<script>
var a=20;
if(a==10){
document.write("a is equal to 10");
}
else if(a==15){
document.write("a is equal to 15");
}
else if(a==20){
document.write("a is equal to 20");
}
else{
document.write("a is not equal to 10, 15 or 20");
}
</script>
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