jquery按钮控制text文本框商品数量增加或减少，加了很多判断，记录一下
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<link href="http://www.jsfoot.com/skin/css/style.css" type="text/css" rel="stylesheet" />
<style type="text/css">
*{margin:0;padding:0;}
a,img{border:0;text-decoration:none;}
body{font:12px/180% Arial, Helvetica, sans-serif, "新宋体";}
/* p_number */
.p_number{border:solid 1px #ddd;padding:10px 0 0 10px;480px;height:80px;margin:40px auto;}
.p_number .f_l{float:left;}
.p_number .add_chose{105px;}
.p_number .add_chose a{float:left;margin:5px 0 0 0;display:block;15px;height:15px;line-height:99em;overflow:hidden;background:url(http://www.jsfoot.com/jquery/demo/2013-01-05/images/reduce-add.gif) no-repeat;}
.p_number .add_chose a.reduce{background-position:0 0;}
.p_number .add_chose a.reduce:hover{background-position:0 -16px;}
.p_number .add_chose a.add{background-position:-16px 0;}
.p_number .add_chose a.add:hover{background-position:-16px -16px;}
.p_number .add_chose .text{float:left;margin:0 5px;display:inline;border:solid 1px #ccc;padding:4px 3px 4px 8px;40px;line-height:18px;font-size:14px;color:#990000;font-weight:800;}
.p_number .buy{line-height:2em;}
.p_number .buy .total-font{font-family:Arial;font-size:26px;}
.p_number .buy .jifen{margin-left:20px;color:#ACACAC;}
.p_number .buy .jifen b{margin:0 3px;}
</style>
<script type="text/javascript" src="jqlx/jquery-1.8.0.js"></script>
<script>
(function($){
function shownum(unprice_id,num_id,price_id,jifen_id){
this.unprice_id=unprice_id;
this.num_id=num_id;
this.price_id=price_id;
this.jifen_id=jifen_id
}
shownum.prototype={
changeprice:function(){
var now_unit= parseInt($("#"+this.unprice_id).text().slice(1));
var now_num=$("#"+this.num_id).val();
$("#"+this.price_id).text("￥"+now_unit*now_num);
$("#"+this.jifen_id).text(now_unit*now_num);
}
}
$(function(){
gouwu();
function gouwu(){
var shownum1=new shownum("price_item_1","qty_item_1","total_item_1","total_points");
shownum1.changeprice();
$(".add").click(function(){
$("#qty_item_1").val(function(index,value){
value++;
return value;
});
shownum1.changeprice();
})
$("#qty_item_1").keyup(function(e){
if(e.which==38){
$(".reduce").trigger("click")
}else if(e.which==40){
$(".add").trigger("click")
}else{
if(e.which<48 || e.which>57){
$(this).val(function(index,value){
var len=value.length;
return value.replace(/[^0-9]/ig, "");//剔除非数字
});
}
shownum1.changeprice();
}
})
$(".reduce").click(function(){
$("#qty_item_1").val(function(index,value){
value--;
value=value<0?0:value;
return value;
});
shownum1.changeprice();
})
}
})
})(jQuery)
</script>
</head>
<body>
<div class="shortcut">
<h1><a href="http://www.jsfoot.com/jquery/form/more/2013-01-05/880.html">jquery按钮控制text文本框商品数量增加或减少</a></h1>
<span class="right">
<a href="http://www.jsfoot.com/jquery/form/more/2013-01-05/880.html">
<strong>下载特效</strong>
</a>
</span>
<div class="clr"></div>
</div><!--/ Codrops top bar -->
<div class="headeline"></div>
<div class="p_number">
<div style="height:36px;font-size:16px;">商品单价：<strong id="price_item_1">￥350.00</strong></div>
<div class="f_l add_chose">
<a class="reduce" href="javascript:void(0)">-</a>
<input type="text" name="qty_item_1" value="1" id="qty_item_1"class="text" />
<a class="add" href="javascript:void(0)">+</a>
</div>
<div class="f_l buy">
总价：<span class="total-font" id="total_item_1">￥89.00</span>
<input type="hidden" name="total_price" id="total_price" value="" />
<span class="jifen">购买商品可获得：<b id="total_points">18</b>积分</span>
</div>
</div>
<!--演示内容结束-->
</body>
</html>