转义

escapeHTML: function(a){  
    a = "" + a;  
    return a.replace(/&/g,"&").replace(//g,">").replace(/"/g,""").replace(/'/g,"'");;  
} 

反转义

unescapeHTML: function(a){  
    a = "" + a;  
    return a.replace(/&lt;/g,"<").replace(/&gt;/g,">").replace(/&amp;/g,"&").replace(/&quot;/g,'"').replace(/&apos;/g,"'");  
}

匹配url

var str = 'fasfahttps://www.baidu.com欢迎'
var reg = /(http:\/\/|https:\/\/)((\w|=|\?|\.|\/|&|-)+)/g
str.replace(reg,'')