test：測試string是否包含有匹配結果，包含返回true，不包含返回false。 

<script type="text/javascript">
	var str = "bbs.byr.cn";
	var reg = /b/;
	var ret = reg.test(str);
	alert(ret); //true
</script>

<script type="text/javascript">
	var str = "ThIS isn't me"; 
	var reg = /is/ig;
	var ret = str.match(reg);
	alert(ret); //IS, is
	console.log(ret); //["IS", "is"] 
</script> 
 

<script type="text/javascript">
	var str = "This isn't me";
	var reg = /is/;
	var ret = str.search(reg);
	alert(ret);//2
</script>

<script type="text/javascript">
	var str = "i love china!";
	var pattern = /i/g;
	var ret = str.replace(pattern, "I");
	alert(ret); //I love chIna!
</script>
 

<script type="text/javascript">
	var  str = 'http://www.baidu.com/';
	var  reg = /\W/;
	var  ret = str.split(reg);
	console.log(ret); //["http", "", "", "www", "baidu", "com", ""] 
</script>

<script type="text/javascript">
	var str = "i love china!"; 
	var reg = /i\B/g; 
	var ret = reg.exec(str); 
	alert(ret); // i
	console.log(ret); //["i", index: 9, input: "i love china!"] 
</script>