<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>