I'm writing a javascript/php file uploader and I want to start this project off on the right track. I've started with this, a js Uploader object which will handle ajax calls, display progress, show error messages, etc. I'm just hoping to get some feedback on the way I'm setting up my scripts. Thank you in advance!

function Uploader(method) {

if(arguments.callee._singleton) return arguments.callee._singleton;
var _this = arguments.callee._singleton = this;

_this.opts = {
    form:"#uploader",
    filePath:"public/uploads/",
    errorCodes:{
        1:"No file/folder selected",
        2:"Invalid file/folder type",
        3:"File/folder exceeds upload size"
    }   
}

_this.methods = {
    
    init: function(options) {
        for(var o in options) {
            _this.opts[o] = options[o];
        }
        
        _this.methods.setup();
    },
    
    setup: function() {
        
    }
    
}   

if(_this.methods[method]) return _this.methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
else if(typeof method === "object" || !method) return methods.init.apply(this, arguments);

}

I'm writing a JavaScript/PHP file uploader and I want to start this project off on the right track. I've started with this, a JavaScript Uploader object which will handle Ajax calls, display progress, show error messages, etc. I'm just hoping to get some feedback on the way I'm setting up my scripts.

function Uploader(method) {

if(arguments.callee._singleton) return arguments.callee._singleton;
var _this = arguments.callee._singleton = this;

_this.opts = {
    form:"#uploader",
    filePath:"public/uploads/",
    errorCodes:{
        1:"No file/folder selected",
        2:"Invalid file/folder type",
        3:"File/folder exceeds upload size"
    }   
}

_this.methods = {
    
    init: function(options) {
        for(var o in options) {
            _this.opts[o] = options[o];
        }
        
        _this.methods.setup();
    },
    
    setup: function() {
        
    }
    
}   

if(_this.methods[method]) return _this.methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
else if(typeof method === "object" || !method) return methods.init.apply(this, arguments);

}