basic javascript regex: global, case insensitive

regex.js

/**
 * Replace single instance, case sensitive
 */
var sentence = "Hello my name is petar petar"
var findTilda = /petar/;   
sentence = sentence.replace(findTilda, '&');
alert(sentence); //Hello my name is & petar

/**
 * Replace all instances, case sensitive
 */
var sentence = "Hello my name is petar petar"
var findTilda = /petar/g;   
sentence = sentence.replace(findTilda, '&');
alert(sentence); //Hello my name is & &


/**
 * Replace all instances, case insensitive
 */
var sentence = "Hello my name is peTar Petar"
var findName = /Petar/gi;   
sentence = sentence.replace(findName, '&');
alert(sentence); //Hello my name is & &