Javascript String Partial Word Match

WordMatch.js

function wordMatch(s1,s2){
    var a1=s1.toLowerCase().split(/[^A-Za-z]/);
    var a2=s2.toLowerCase().split(/[^A-Za-z]/);
    
    for(var i=0;i<a1.length;i++)
        if(a2.indexOf(a1[i])>=0)
            return true;
    return false;
}

var str1="Kolkata, West Bengal, India";
var str2="goa,west";

console.log(wordMatch(str1,str2));