Javascript Regular Expressions Search Sub String

let myRegexp = /Java(Script)?/g;
let myString = "Both Java and JavaScript share the same name, but are quite different.";

myRegexp.exec(myString);//w w w  .j a va 2s .co  m
console.log( myRegexp.lastIndex);  // 9
myRegexp.exec(myString);
console.log( myRegexp.lastIndex);  // 24
myRegexp.exec(myString);
console.log( myRegexp.lastIndex );  // 0