


JavaScript regular method replace implements search keyword highlighting
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,具体内容详情大家参考下本文
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
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>
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