To split a string in javascript, we use split() method which splits the string into an array of substrings.

Syntax: string.split(separator);

Where separator specifies the character(s) to use for separating the string, and if this separator ( or delimeter) is found in the main string , separator is removed from that string and an array is return consisting of substrings. If separator is not found, the array contains one element consisting of the entire string.

Eg: Below is the function for using split() method:

function splitString() {
    var strToSplit = "My Split Program.";
    var separator=" ";
    var strResult = strToSplit.split(separator);
    for(var i=0;i<strResult.length;i++)
    {
        alert(strResult[i] );
    }
}

Output of above function:
strResult[0]= My
strResult[1]=Split
strResult[2]=Program.