仿淘宝商品数量选择框加减

function getRandom(n){
        return Math.floor(Math.random()*n+1)
     }
 



	var inputp={
		indexInput:0,
		
		addNew:function(obj,stepNum){
			this.initNew(obj,stepNum);
			this.indexInput++;
		},
		getDigit:function(val,num){
			var digitNum=0;
			if(num.toString().split(".")[1]){
				digitNum=num.toString().split(".")[1].length;
			}
			 
			if(digitNum>0){
		 		val=val.toFixed(digitNum);
			}
			return val;
			
		},