How do I replace a character at a particular index in JavaScript?

Question

I have a string, let\'s say Hello world and I need to replace the char at index 3. How can I replace a char by specifying a index?

var str = \"h         


        

Answer 1

This works similar to Array.splice:

String.prototype.splice = function (i, j, str) {
    return this.substr(0, i) + str + this.substr(j, this.length);
};