JSFiddle - React, Tailwind, and code Playground

JavaScript

var String1 = "Java1String",
String2 = "Java2String",
String3 = "Java3String";

var j = 0;

for(var i = 0; i < String1.length; i++){
    if(String1.charAt(i) != String2.charAt(j))
        alert(String1.charAt(i) +"  !=  "+ String2.charAt(j));
        j++;
}