How to use regular expressions to highlight JavaScript code
这次给大家带来用正则表达式让JavaScript的代码高亮，怎样用正则表达式让JavaScript的代码高亮？用正则表达式让JavaScript的代码高亮的注意事项有哪些，下面就是实战案例，一起来看一下。
今天想改一下JS的高亮的配色，憋了一下午憋出了这个这个正则表达式。
下面这老长老长了的玩意儿是个正则表达式，看到了别吓坏了。
/(\/\/.*|\/\*[\S\s]+?\*\/)|((["'])(?:\\.|[^\\\n])*?\3)|\b(break|continue|do|for|in|function|if|else|return|switch|this|throw|try|catch|finally|var|while|with|case|new|typeof|instance|delete|void)\b|\b(Object|Array|String|Number|Boolean|Function|RegExp|Date|Math|window|document|navigator|location)\b|\b(true|false)\b|\b(null|undefined|NaN)\b|(?:[^\W\d]|\$)[\$\w]*|(0[xX][0-9a-fA-F]+|\d+(?:\.\d+)?(?:[eE]\d+)?)|(?:[^\)\]\}]|^)(\/(?!\*)(?:\\.|[^\\\/\n])+?\/[gim]*)|[\S\s]/g
给大家看一下完整的代码
<style>body {font:14px/18px Consolas;}</style><script id="code">//读入当前代码var code=document.getElementById("code").innerHTML;//修正换行的浏览器差异，去掉头尾的换行和空格code=code.replace(/\r\n|[\r\n]/g,"\n").replace(/^\s+|\s+$/g,"");//开始主匹配code=code.replace(/(\/\/.*|\/\*[.\s]+?\*\/)|((["'])(?:\\.|[^\\\n])*?\3)|\b(break|continue|do|for|in|function|if|else|return|switch|this|throw|try|catch|finally|var|while|with|case|new|typeof|instance|delete|void)\b|\b(Object|Array|String|Number|Boolean|Function|RegExp|Date|Math|window|document|navigator|location)\b|\b(true|false)\b|\b(null|undefined|NaN)\b|(?:[^\W\d]|\$)[\$\w]*|(0[xX][0-9a-fA-F]+|\d+(?:\.\d+)?(?:[eE]\d+)?)|(?:[^\)\]\}]|^)(\/(?!\*)(?:\\.|[^\\\/\n])+?\/[gim]*)|[.\s]/g,function(){ var a,l,i,s; a=arguments; //循环匹配到的位置 for(i=1;i<=9;i++)if(s=a[i]){ s=htmlEncode(s); //每个获取匹配的位置都着上不同的颜色 switch(i){ case 1://注释 return s.fontcolor("#998877").italics(); case 2:case 3://字符串 return s.fontcolor("#AA5544"); case 4://关键词 return s.fontcolor("#333388"); case 5://内置对象 return s.fontcolor("#5555AA"); case 6://布尔值 return s.fontcolor("#DD6600"); case 7://空值 return s.fontcolor("#BB4433"); case 8://数字 return s.fontcolor("#CC3322"); case 9://正则表达式 //这个比较特殊，匹配到的和获取的有些不同 //匹配的时候，前面有个非获取匹配，所以我们要保留非获取匹配的部分 return htmlEncode(a[0]).replace(s,s.fontcolor("#33AA33")); }; }; //没有获取匹配就直接转义输出 return htmlEncode(a[0]);});
//输出结果document.write(code);
//HTML的转义函数function htmlEncode(e){ var i,s; for(i in s={ "&":/&/g,""":/"/g,"'":/'/g, "<":/</g,">":/>/g,"<br/>":/\n/g, " ":/ /g," ":/\t/g })e=e.replace(s[i],i); return e;};</script>相信看了这些案例你已经掌握了方法，更多精彩请关注php中文网其它相关文章！
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