试试

function toUtf8(str) {

var out, i, len, c;

out = “”;

len = str.length;

for(i = 0; i < len; i++) {

c = str.charCodeAt(i);

if ((c >= 0x0001) && (c <= 0x007F)) {

out += str.charAt(i);

} else if (c > 0x07FF) {

out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));

out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));

out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));

} else {

out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));

out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));

}

}

return out;

}