javascript µÄperlÀàÐ͵ÄÕýÔò±í´ïʽ

£¨1£©var recat = new RegExp("cat");    //¼òµ¥¶¨Òå¡£
        var recat = new RegExp("cat","gi");//g->global,i->case insensitive.
        var recat = /cat/gi;                         //perlģʽ
£¨2£©var sToMatch = "cat";
        var reCat = /cat/;
        alert(reCat.test(sToMatch));   //true
        var sToMatch = "a bat, a cat, a Fat Cat, a faT caT";
        var reAt = /at/; 
        var arrMatches = reAt.exec(sToMatch); //Ö»·µ»ØµÚÒ»¸öat³öÏÖµÄʵÀý£¬bat. ×¢ÒâÕâÀïʹÓÃexecʱ£¬²ÎÊýÊÇÔ­×Ö·û´®
        var sToMatch = "a bat, a cat, a Fat Cat, a faT caT";
        var reAt = /at/gi; 
        var arrMatches = sToMatch.match(reAt); //ÕâÀïʹÓÃmatchʱºò£¬²ÎÊýÊÇÕýÔò±í´ïʽ
        var sToMatch = "a bat, a cat, a Fat Cat, a faT caT";
        var reAt = /at/gi;
        alert(sToMatch.search(reAt));                  //ÕâÀïºÍindexOf()ÓÐЩÏàËÆ £¬Êä³ö3
£¨3£©var sToChange = "The sky is blue. ";
        alert(sToChange.replace("blue","gray")); //output "The sky is gray. "
        var sToChange = "The sky is blue. ";
        var reRed = /red/;
        var sResultText = sToChange.replace(reRed,function(sMatch){         //ÕâÀïreplace()µÄµÚ¶þ¸ö²ÎÊýÊÇÒ»¸öÄäÃûº¯Êý£¬¸Ã
              return "blue";                                               &