JavaScript regular method replace implements search keyword highlighting

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JavaScript regular method replace implements search keyword highlighting_regular expression

韦小宝

Dec 04, 2017 am 11:01 AM

javascriptjsreplace

这里介绍的是JavaScript的正则表达式的replace方法 ,和实现搜索关键字高亮的功能.先介绍一下正则表达式的replace方法，以下本文含有JavaScript源码和JavaScript源码讲解，一起来看本文详细吧

前言

正则表达式是字符串处理工具中强有力的工具.也有人认为这只是一个小玩具,但不管怎么说都离不开它.

这里介绍的是JavaScript的正则表达式的replace方法 ,和实现搜索关键字高亮的功能.

先介绍一下正则表达式的replace方法

JavaScript regular method replace implements search keyword highlighting_regular expression

JavaScript regular method replace implements search keyword highlighting_regular expression

w3school原文链接介绍

正则表达式如何使用特殊字符$来表示原来的文本,这是实现搜索高亮的关键,

var str = "asad sad 123 sd qwe21";
str.replace(/\d+/img,"数字");
//这里正确的匹配到了数字,且替换成了中文的数字
console.log(str);//"asad sad 数字 sd qwe数字"
------------------------------------------------------
//看一下如何使用$1,表示被捕获的字符串
var str = "asad sad 123 sd qwe21";
str.replace(/\d+/img,"数字$1数字");
console.log(str);//"asad sad 数字$1数字 sd qwe数字$1数字"
//很显然并没有成功,$1 还是$1,那么如何正确使用呢?
------------------------------------------------------
var str = "asad sad 123 sd qwe21";
str.replace(/(\d+)/img,"数字$1数字");
//这里就正确的匹配了数字并且用$1 表示原字符串并替换
console.log(str);///"asad sad 数字123数字 sd qwe数字21数字"
/*
()在正则里面表示捕获性元组,可以用$1 特殊字符来表示被替换的内容,可以有多个()元组,也就是可以有多个$1,$2 */

开始小试身手

<!DOCTYPE html>
<html lang="en">
<head>
</head>
<body>
 <style>
 b{
 color:red;
 }
 </style>
<p id="poetry">
春江花月夜<br>
作者：张若虚<br>
春江潮水连海平，海上明月共潮生。 <br>
滟滟随波千万里，何处春江无月明！ <br>
江流宛转绕芳甸，月照花林皆似霰； <br>
空里流霜不觉飞，汀上白沙看不见。 <br>
江天一色无纤尘，皎皎空中孤月轮。 <br>
江畔何人初见月？江月何年初照人？ <br>
人生代代无穷已，江月年年只相似。 <br>
</p>
<input type ="text" id="input" />
</body>
</html>
<script>
//input 输入要查找的字符串
input.onchange = function(){
 //获取要查找的字符串
 var searchVal = input.value;
 // 获取要查找的内容
 var text = poetry.innerHTML;
 //将之前的查找高亮的字符串,取消高亮
 text = text.replace(/<b[^>]*>([^>]*)<\/b[^>]*>/ig,"$1");
 poetry.innerHTML = text;
 //初始化正则表达式,加上括号(),形成可捕获元组.ig表示全局匹配和不区分大小写
 var reg = new RegExp("("+searchVal +")","ig");
 //高亮要查找的字符串
 text = text.replace(reg,"<b>$1</b>");
 poetry.innerHTML = text;
}
</script>

以上所述是小编给大家介绍的JavaScript正则方法replace实现搜索关键字高亮显示，希望对大家有所帮助。

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JavaScript正则方法replace实现搜索关键字高亮显示

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