5. JavaScript RegExp 类型

一般的分组()即括号中没有?:的使用时regexp对象都会将分组内匹配到的内容记录下来
re = /(abc){2}/;//将匹配abcabc
这时RegExp会储存abc
var str = "abcabc";
re.test(str);
alert(RegExp.$1);

加上?:后
re = /(?:abc){2}/;
RegExp  就不会储存这个分组了
var str = "abcabc";
re.test(str);
alert(RegExp.$1);

var pattern1 = new RegExp("bc","i");
alert(pattern1.global);
alert(pattern1.ignoreCase);

var text = "mom and dad and baby";
var pattern = new RegExp("mom(and dad(and baby)?)?","gi");
var matches = pattern.exec(text);
alert(matches);
alert(matches.index);
alert(matches.input);
alert(matches[0]);
alert(matches[1]);
alert(matches[2]);