正则表达式- 将div#demo.demo转化成<div id="demo" class="demo"></div>

    var str = ("div#demo.demo");    str.replace(/^(\w+)#(\w+)\.(\w+)$/,function(match,$1,$2,$3){        return "<"+$1+" id=\"" + $2+ "\" class=\""+ $3+ "\"><\/" + $1 +">"    })    console.log(str);

var str = ("div#demo.demo").replace(/^\b(\w+)\b#\b(\w+)\b\.\b(\w+)\b$/,function(match,$1,$2,$3){        return "<"+$1+" id=\"" + $2+ "\" class=\""+ $3+ "\"><\/" + $1 +">"    })    console.log(str);