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js中的正则表达式

2016-05-06 20:51 537 查看 
<pre class="html" name="code"><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>dom3.html</title>

<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">

<link rel="stylesheet" type="text/css" href="./form2css.css">
<script language="javascript" type="text/javascript">
//检验是否为邮箱
function test(){
var nei = document.getElementById("neirong").innerText;
var regexp = /^[a-zA-Z0-9_-]+@[a-zA-Z0-9]+\.(com|cn|net|org)$/;
if(regexp.test(nei)){
alert("这个是邮箱");
}
else{
alert("这不是邮箱");
}

}
//检验即可以匹配这个，又可以匹配那个，这是你就需要用到选择匹配符号 |
function test1(){
var nei = document.getElementById("neirong").innerText;
var regexp = /(han|韩|含)/gi;
var ne;
while(ne = regexp.exec(nei)){
alert(ne[0]);
}
}
//请编写一个正则表达式，可以匹配三个连续的字符
function test2(){
alert(1);
var nei = document.getElementById("neirong").innerText;
var regexp = /([\d\D]){3}/gi;
var ne;
while(ne = regexp.exec(nei)){
alert(ne[0]);
}
}

</script>

</head>

<body>
<textarea cols="30" rows="30" id="neirong"></textarea>
<input type="button" value="测试" onclick="test2()"/>
</body>
</html>


function test(){var k = document.getElementById("neirong").innerText;// var regexp = /(\d){4}/gi;//连续四位都是数字的字串var regexp = /(\d){4}/gi;var g;while( g = regexp.exec(k)){document.writeln(g);document.writeln(g.lastIndex);}}


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>dom3.html</title>

<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">

<link rel="stylesheet" type="text/css" href="./form2css.css">
<script language="javascript" type="text/javascript">
//子表达式  捕获 反向引用
//正则表达式中//gi  //中用()包围的称为子表达式
// /(\d)(\d)\2\1/gi (\d)第一个子表达式 (\d)第二个子表达式 \2反向引用第二个子表达式的内容 \1反向引用第一个子表达式的内容  js引擎会捕获子表达式的内容并存进去内容里面
function test(){
var nei = document.getElementById("neirong").innerText;
var regexp = /你好/gi;
alert(nei.search(regexp));
}

function test1(){
var nei = document.getElementById("neirong").innerText;
var regexp = /(\d){4}/gi;
var shuzu = nei.match(regexp) ;
for(var i=0;i<shuzu.length;i++){
alert(shuzu[i]);
}

}

function test2(){
var nei = document.getElementById("neirong").innerText;
var regexp = /(\d){4}/gi;
var xin  = nei.replace(regexp , "这是四个数");
document.getElementById("neirong").innerText = xin;
}

function test3(){
var nei = document.getElementById("neirong").innerText;
var regexp = /(\d){4}/gi;
var xin  = nei.split(regexp);
document.getElementById("neirong").innerText = xin;
}

//获取类似5445 6336这样的字符串
//var regexp = /(\d)(\d)\2\1/gi;
//获取类似55667788的字符串
//var regexp1 = /(\d)\1(\d)\2(\d)\3(\d)\4/gi;
//获取前五位是任意数字 然后一个'-' 然后是类似333444555的字符串
//var regexp2 = /(\d){5}-(\d)\2\2(\d)\3\3(\d)\4\4/gi;
function test4(){

var nei = document.getElementById("neirong").innerText;
var regexp = /(\d)(\d)\2\1/gi;
var regexp1 = /(\d)\1(\d)\2(\d)\3(\d)\4/gi;
var regexp2 = /(\d){5}-(\d)\2\2(\d)\3\3(\d)\4\4/gi;
var kk  ;

while(kk= regexp2.exec(nei)){
alert(kk[0]);
}
}

</script>

</head>

<body>
<textarea cols="30" rows="30" id="neirong"></textarea>
<input type="button" value="测试" onclick="test4()"/>
</body>
</html>


var regexp = /\./gi; //表示找出.字符

var regexp = /./gi;  //表示找出查找单个字符，除了换行和行结束符。

js正则表达式中需要用到转义符号的字符有以下：

.  *  + (  )  $  /  \  ?  [ ]  ^  {  }   就是说需要在字符串中找到以下字符的时候要在该个字符的前面加上\   例如：/\(/gi  这个是要找字符串中是否含有(字符

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                         标签： 
                                                javascript
                                                正则表达式
                                                

                        

                    


                

            


            

                
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