js仿淘宝商品购买多条件选择代码特效

主要js代码
var mSpan = document.getElementById('model').getElementsByTagName('span');
	var cSpan = document.getElementById('color').getElementsByTagName('span');
	var rSpan = document.getElementById('rom').getElementsByTagName('span');
	var bSpan = document.getElementById('banben').getElementsByTagName('span');
	var aSpan = document.getElementsByTagName('span');
	var oModel = document.getElementById('model');
	var oRom = document.getElementById('rom');
	var oPrice = document.getElementById('price');

	mSpan[0].className = 'on';
	cSpan[0].className = 'on';
	rSpan[0].className = 'on';
	bSpan[0].className = 'on';

	for (var i=0;i<aSpan.length;i++ )
	{
		
		aSpan[i].onclick = function(){
			var siblings = this.parentNode.children;
			for (var j=0;j<siblings.length;j++ )
			{
				siblings[j].className = '';
			}
			this.className = 'on';
			
			if ( this.parentNode == oModel || this.parentNode == oRom )
			{
				price();
			}
		};
	};

	function price(){
		var p1 = 0;
		var p2 = 0;
		for (var i=0;i<mSpan.length;i++ )
		{
			if ( mSpan[i].className == 'on' )
			{
				p1 = i?6088:5288;
				break;
			};
		};
		for (var i=0;i<rSpan.length;i++ )
		{
			if ( rSpan[i].className == 'on' )
			{
				switch ( i )
				{
					case 0:
						p2 = 0;
						break;
					case 1:
						p2 = 800;
						break;
					case 2:
						p2 = 1600;
						break;
				}
			}
		};
		oPrice.innerHTML = p1+p2;
	};