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>