js 转码

<script type="text/javascript"> 
var easyUTF8 = function(gbk){ 
    if(!gbk){return '';} 
    var utf8 = []; 
    for(var i=0;i<gbk.length;i++){ 
        var s_str = gbk.charAt(i); 
        if(!(/^%u/i.test(escape(s_str)))){utf8.push(s_str);continue;} 
        var s_char = gbk.charCodeAt(i); 
        var b_char = s_char.toString(2).split(''); 
        var c_char = (b_char.length==15)?[0].concat(b_char):b_char; 
        var a_b =[]; 
        a_b[0] = '1110'+c_char.splice(0,4).join(''); 
        a_b[1] = '10'+c_char.splice(0,6).join(''); 
        a_b[2] = '10'+c_char.splice(0,6).join(''); 
        for(var n=0;n<a_b.length;n++){ 
            utf8.push('%'+parseInt(a_b[n],2).toString(16).toUpperCase()); 
        } 
    } 
    return utf8.join(''); 
}; 
document.write(easyUTF8('我爱北京！')); 
</script>