docs: function(from, to, unit){
  		this.startTime = now();
  		this.start = from;
  		this.end = to;
  		this.unit = unit || this.unit || "px";
  		this.now = this.start;
  		this.pos = this.state = 0;
  
  		var self = this;
  		function t(gotoEnd){
  			return self.step(gotoEnd);
  		}
  
  		t.elem = this.elem;
  
  		if ( t() && jQuery.timers.push(t) && !timerId ) {
  			timerId = setInterval(function(){
  				var timers = jQuery.timers;
  
  				for ( var i = 0; i < timers.length; i++ )
  					if ( !timers[i]() )
  						timers.splice(i--, 1);
  
  				if ( !timers.length ) {
  					clearInterval( timerId );
  					timerId = undefined;
  				}
  			}, 13);
  		}
  	}