Encoding javascript utf16 characters for urls

Dug this up from the bowels of the ddbdp webapp code. I wrote it a long time ago, but didn't end up needing it. Seems like it might be useful down the line...

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var firstByteMark = [ 0x00,0x00,0xC0,0xE0,0xF0,0xF8,0xFC ];
var byteMask = 0xBF;
var byteMark = 0x80;

function UTF16toUTF8Bytes(u16){
    var bytes = new Array();
    if (u16 < 128){
        bytes.length = 1;
    } else if (u16 < 2048){
        bytes.length = 2;
    } else { // presuming max js charCode of 65535
        bytes.length = 3;
    }
    switch (bytes.length){
        case 3:
            bytes[2] = ((u16 | byteMark) & byteMask);
            u16 >>= 6;
        case 2:
            bytes[1] = ((u16 | byteMark) & byteMask);
            u16 >>= 6;
        case 1:
            bytes[0] = (u16 | firstByteMark[bytes.length]);
    }
    return bytes;
}
function encode(input){
    var output = new Array();
    var inputArray = input.split(/\s+/);
    for(var i=0;i<inputArray.length;i++){
        var term = '';
        for(var j=0;j<inputArray[i].length;j++){
            var u16 = inputArray[i].charCodeAt(j);
            if (u16 < 128){
                term += inputArray[i].charAt(j);
                continue;
            }
            var utf8bytes = UTF16toUTF8Bytes(u16);
            for(var k=0;k<utf8bytes.length;k++){
                if(utf8bytes[k] < 16){
                    term += "%0";
                } else {
                   term += "%";
                }
                term += utf8bytes[k].toString(16);
            }
        }
        output[i] = term;
    }
    return output;
}