Javascript Tutorial Programme to calculate Factorial of any number


In this tutorial we are going to write a simple javascript programme which can calculate factorial of any number . First we have to know that formula how to find out factorial.

Factorial of 3 = 3 * (3-1) * (3-2) = 6

or 3! = 3*2*1=6

Formula : n! = 1×2×3×4×...×n

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8"/>
<title>Calculate Factorial</title>
</head>
<body>
<b>Factorial Calculator</b><br/>
<input type="text" id="no" placeholder="Enter an Integer "/><br/>
<input type="submit" id="submit" value="Calculate">
<p id="result"></p>
<script>
    document.getElementById("submit").addEventListener("click", calculate);

    function calculate(){
        var n=document.getElementById("no").value;
        var i;
        var fact =1;
        if(n==""){
            alert("Enter an Integer");
        }else{
            while(n>0)
                {
                    fact = fact *n;
                    n-=1;
                }
            document.getElementById("result").innerHTML = fact ;
        }
        
    }
</script>
</body>
</html>

Example Factorial Calculator

 


 Category : Javascript   Posted By : Sanjay   on 2015-08-20 16:09:41


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