Serialize JavaScript objects to XML (for use with Ajax)

The following 3 functions can be added to any JavaScript library to serialize objects to XML for use with Ajax.

--- serialize.js ---

Array.prototype.toXml = function(t){
    var s = new Array(), i, l = this.length, v;
    var t2 = (t.charAt(t.length-1)=='s')?t.substring(0,t.length-1):t;
   
    for(i=0;i<l;i++){
        v = this[i];
        switch (typeof v) {
            case 'undefined':
            case 'function':
            case 'unknown':break;
            case 'object':if(v!=null){s.push(v.toXml(t2));}break;
            case 'string':v = v.toXml();
            default:s.push('<'+t2+'>'+v+'');
        }
    }
    if(s.length>1)return '<'+t+'>'+s.join('')+'';
    return s;
};

Object.prototype.toXml = function(t){
    var sa = new Array(''), se = new Array('');
    if(!t) t=this._tagName||'object';
   
    for(var i in this){               
        if (this.hasOwnProperty(i) && i.charAt(0)!='_') {
            var v = this[i];
            switch (typeof v) {
                case 'undefined':
                case 'function':
                case 'unknown':break;
                case 'object':if(v!=null){se.push(v.toXml(i));}break;
                case 'string':v = v.toXml();
                default: sa.push(' '+i+'="'+v+'"');
            }
        }
    }
    var s = se.join('');
    return '<'+t+sa.join('')+((s!='')?'>'+s+'':'/>');
};

String.prototype.toXml = function(){
    return this.replace('&','&amp;').
      replace('<','&lt;').replace('>','&gt;').
      replace('\'','&apos;').replace('"','&quot;');
};

Sample Usage

<script language="javascript" src="serialize.js"></script>
<script language="javascript">

function Car(make,model,color){
    this.make  = make;
    this.model = model;
    this.color = color;
}

var cars = new Array();
cars.push(new Car('BMW','545i','Silver'));
cars.push(new Car('Toyota','Corrola','Red'));
cars.push(new Car('Honda','Accord','Black'));

//serialize to xml
alert(cars.toXml());

</script>


Note:
1. Private properties are prefixed with an underscore
2. You can add a default TagName for an object using the this._tagName property. For example in the Cars object above, you can add:

this._tagName = 'car';

...