Checks string for pangram #hackerrank #strings

pangram.js

/*
Solution for HackerRank > Algorithms > Strings > Pangrams
https://www.hackerrank.com/challenges/pangrams
*/

function main(input) { 
    var alpha = 'abcdefghijklmnopqrstuvwxyz';
    var i = 0, char, index;

    // Simplify string
    var simple_input = input.toLowerCase().replace(/\s+/g, '');
    
    /*
    Test for each character in the alpha string.
    If the character doesn't exist, break the loop and return 'not panagram'.
    */
    for (i=0; i < alpha.length; i++){
        char = alpha.charAt(i);
        index = simple_input.indexOf(char);
        if (index == -1){
            console.log('not pangram');
            break;
        } else if (i == 25){
            console.log('pangram');
        }
    }
}

main('We promptly judged antique ivory buckles for the next prize    ');