var patt1=new RegExp("e");
document.write(patt1.test("The best things in life are free"));

var patt1=new RegExp("e");
document.write(patt1.exec("The best things in life are free"));

var patt1=new RegExp("e","g");

do
{
result=patt1.exec("The best things in life are free");
document.write(result);
}
while (result!=null)

var patt1=new RegExp("e");
document.write(patt1.test("The best things in life are free"));
patt1.compile("d");
document.write(patt1.test("The best things in life are free"));

var str = "Visit W3School";
var patt1 = /w3school/i;
var patt2 = new RegExp("w3school","i")
document.write(str.match(patt1));

var str="Is this all there is?";
var patt1=/is/gi;
document.write(str.match(patt1));

var str="Is this all there is?";
var patt1=/[a-h]/g;
var patt2=new RegExp("[a-h]","g")
document.write(str.match(patt1));

var str="Is this all there is?";
var patt1=/[^a-h]/g;
document.write(str.match(patt1));

var str="Give 100%!"; 
var patt1=/\w/g;
document.write(str.match(patt1));

var str="Give 100%!"; 
var patt1=/\d/g;
document.write(str.match(patt1));

var str="Visit W3School.\n Learn JavaScript."; 
var patt1=/\n/g;
document.write(str.search(patt1));

var str="1, 100 or 1000?"; 
var patt1=/10?/g;
document.write(str.match(patt1));

var str="100, 1000 or 10000?";
var patt1=/\d{4}/g; 
document.write(str.match(patt1));

var str="Is this all there is";
var patt1=/is(?= all)/;
document.write(str.match(patt1));