分几种情况说明

1.如果re中不是全局的也就是不带g

var str = "cat3 hat4";
        var re = /\w+\d/;
        var ex = re.exec(str);
        var mt = str.match(re);
        console.log(ex);
        console.log(mt);

2.如果re中带g, 也就是全局的

var str = "cat3 hat4";
        var re = /\w+\d/g;
        var ex = re.exec(str);
        var mt = str.match(re);
        console.log(ex);
        console.log(mt);

3.如果re中带分组但是不带g

var str = "cat3 hat4";
        var re = /\w+(\d)/;
        var ex = re.exec(str);
        var mt = str.match(re);
        console.log(ex);
        console.log(mt);

4.如果re中带分组也带g

var str = "cat3 hat4";
        var re = /\w+(\d)/g;
        var ex = re.exec(str);
        var mt = str.match(re);
        console.log(ex);
        console.log(mt);

还有他们2个exec是正则对象的方法    而match是字符串的方法

Javascript正则中的exec和match

原文：http://blog.csdn.net/atvance016/article/details/40840113