写完正则在浏览器上检测自己写得对不对实在是不方便，于是就撸了一个JS正则小demo出来。
demo
代码部分
首先把布局样式先写好。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>js正则查找替换工具</title>
<link rel="stylesheet" type="text/css" href="./RegExp.css">
<script type="text/JavaScript" src="./RegExp.js"></script>
</head>
<body>
<form name="tester" action="" method="post" onSubmit="processRegex(this);return false">
<table border="1" cellpadding="4" cellspacing="0" width="550">
<tr>
<th class="Dialog">js正则查找替换工具</th>
</tr>
<tr>
<td class="Dialog">
<span class="header">请输入正则表达式:</span>
<br>
<input name="RegEx" type="text" size="62" style="font-size:13px">
<input type="checkbox" name="caseSensitive" id="caseSensitive" value="Yes">
<label for="caseSensitive">区分大小写</label>
<input type="radio" name="operation" id="operationFind" value="find" checked onClick="hideReplaceFields()">
<label for="OperationFind">查找</label>
<input type="radio" name="operation" id="operationReplace" value="replace" onClick="showReplaceFields()">
<label for="OperationReplace">替换</label>
<br>
<span class="header" id="replaceheader">请输入替换的正则表达式:</span>
<br>
<input id="RegExReplace" name="RegExReplace" type="text" size="62" style="font-size:13px">
<span class="header" style="margin-top: 3px;display: block;">填写你想查找或替换的文本:</span>
<textarea name="searchText" cols="70" rows="6"></textarea>
<img src="http://files.cnblogs.com/files/MuYunyun/pkq.gif" style="margin-left: 10px">
<br>
<input name="submit" type="submit" style="font-weight: bold" value="开始">
</td>
</tr>
</table>
</form><br>
<span id="output"></span>
<script language="JavaScript">
hideReplaceFields();
</script>
</body>
</html>
布局
body {
font-family: arial;
font-size: 12px;
}
input {
font-size: 11px;
}
textarea {
font-size: 11px;
}
th {
background:#8888FF;color:white;text-align:left
}
td {
background:#CCCC99;color:black;font-size:12px
}
.RowA {
background: #CCCC99
}
.RowB {
background: #EEEEBB
}
.header {font-weight: bold}
样式
接着就是用js分别构造查找和替换两个函数，用到了RegExp对象的一些属性，思路还是比较简单的。代码如下：
// 没选中替换则不能输入
function hideReplaceFields() {
document.getElementById('RegExReplace').disabled = true;
document.getElementById('replaceheader').disabled = true;
}
// 点击替换则能输入
function showReplaceFields() {
document.getElementById('RegExReplace').disabled = false;
document.getElementById('replaceheader').disabled = false;
}
// 查找
function processRegexFind(text, regex, flags) {
var reg = new RegExp(regex, flags);
var lastIdx = -1;
var iCount = 0;
var result = "";
var output = '<div style="height:200px;overflow-y:auto;width:550"><table border="0" cellpadding="2" cellspacing="0" width="550"><tr><th width="*">匹配内容</th><th>位置</th><th>长度</th></tr>'
// 循环
while (lastIdx != 0) {
var mtch = reg.exec(text);
if (reg.lastIndex !== 0) { //lastIndex属性存放一个整数，它声明的是上一次匹配文本之后的第一个字符的位置。
iCount++;
if (iCount % 2) {
style = "RowA"
} else style = "RowB";
// 输出
output += '<tr class="' + style + '"><td>' + RegExp.lastMatch + '</td><td>' + (reg.lastIndex - RegExp.lastMatch.length) + '</td><td>' + RegExp.lastMatch.length + '</td></tr>';
}
lastIdx = reg.lastIndex;
}
output += '</table></div>';
if (iCount !== 0) {
result = "匹配个数: " + iCount + output;
} else result = '未找到匹配的项';
return result;
}
// 替换
function processRegexReplace(text, regexfind, regexreplace, flags) {
var re = new RegExp(regexfind, flags);
var newstr = text.replace(re, regexreplace);
var result = '<div style="height:200px;overflow-y:auto;width:550"><table border="0" cellpadding="2" cellspacing="0" width="550"><tr><th>替换后：</th></tr><tr><td>' + newstr + '</td></tr>';
return result;
}
// 人口
function processRegex(form) {
var output = '';
var flags;
if (form.caseSensitive.checked) flags = "g";
else flags = "gi";
//判断是查找还是替换
if (form.operationFind.checked) {
output = processRegexFind(form.searchText.value, form.RegEx.value, flags);
} else if (form.operationReplace.checked) {
output = processRegexReplace(form.searchText.value, form.RegEx.value, form.RegExReplace.value, flags);
}
document.getElementById('output').innerHTML = output;
return false;
}
用这小工具学习js正则可以事半功倍哟。大家新年快乐！