js 购买数量的加减修改

jquery.goods.js文件
$(function() {
    $('.goods-first #goods-text .goods-price').hover(function(){
        $(this).toggleClass('curr');
    })
    $('#goodsDescription>.tabs>ul>li>a').click(function(){
        $('#goodsDescription>.tabs>ul>li').removeClass('selected');
        $(this).parent('li').addClass('selected');
        var dataName = $(this).attr('dataname');
        $("#goodsDescription>.goods-box").hide();
        switch(dataName){
            case 'aftermarket':
                $("html,body").animate({scrollTop:$("#goodsAftermarket").offset().top+1},200);
                break;
            case 'weibo':
                $("html,body").animate({scrollTop:$("#goodsWeibo").offset().top+1},200);
                break;
            case 'ask':
                $("html,body").animate({scrollTop:$("#goodsAsk").offset().top+1},200);
                break;
            case 'reviews':
                $("html,body").animate({scrollTop:$("#goodsReviews").offset().top+1},200);
                break;
            default:
                $("#goodsDescription>.goods-box").show();
                $("html,body").animate({scrollTop:$("#goodsDescription").offset().top},200);
        }
    })
})
function buy(goodsId,gaId,parentId,once){
    var number = Number($('#pamount').val()) > 0 ? Number($('#pamount').val()) : 1;
    $.post(siteUrl + 'ajax/cart_add_goods.html', {gid:goodsId,gaid:gaId,number:number,pid:parentId,once:once}, buyResponse, 'json');
}
function buyResponse(result) {
    if(result.error > 0) {
        if(result.error == 1) {
            if(confirm('参数错误，请刷新后重新购买，立刻刷新？')){
                window.location.reload;
            }
        }else if(result.error == 2) {
            cart_info_ajax()
            var modalTip = $('#modalBuyTip');
            modalTip.children('.modal-body').html(result.message);
            $('#modalBuyTipLink').attr('href',siteUrl + 'buy/cart.html');
            modalTip.modal({
                backdrop:false,
                show:true
            });
        } else {
            alert(result.message);
        }
    } else {
        if(result.once){
            window.location.href = siteUrl + 'buy/checkout.html';
        }else{
            cart_info_ajax()
            var modalTip = $('#modalBuyTip');
            modalTip.children('.modal-body').html(result.message);
            $('#modalBuyTipLink').attr('href',siteUrl + 'buy/cart.html').html('去购物车结算');
            modalTip.modal({
                backdrop:false,
                show:true
            });
        }
    }
}

var setAmount = {
        min : 1,
        max : 999,
        reg : function(x) {
        return new RegExp("^[1-9]\\d*$").test(x);
    },
    amount : function(obj, mode) {
        var x = $(obj).val();
        if(this.reg(x)) {
            if(mode) {
                x++;
            } else {
                x--;
            }
        } else {
            alert("请输入正确的数量！");
            $(obj).val(1);
            $(obj).focus();
        }
        return x;
    },
    reduce : function(obj,goodsId) {
        var x = this.amount(obj, false);
        if(x >= this.min) {
            $(obj).val(x);
        } else {
            alert("请输入正确的数量！");
            $(obj).val(1);
            $(obj).focus();
        }
    },
    add : function(obj,goodsId) {
        var x = this.amount(obj, true);
        if(x <= this.max) {
            $(obj).val(x);
        } else {
            alert("商品数量最多为" + this.max);
            $(obj).val(999);
            $(obj).focus();
        }
    },
    modify : function(obj) {
        var x = $(obj).val();
        if(x < this.min || x > this.max || !this.reg(x)) {
            alert("请输入正确的数量！");
            $(obj).val(1);
            $(obj).focus();
        }
    }
}

productsview.php文件
..........
<SCRIPT type=text/javascript src="images/jquery.goods.js"></SCRIPT>
..........
<A class="reduce block fl"
  onclick="setAmount.reduce('#pamount')" href="javascript:void(0)">-</A> <INPUT
  id=pamount class=fl onKeyUp="setAmount.modify('#pamount')" value=1 type=text
  name=number style="height:30px"> <A class="add block fl" onClick="setAmount.add('#pamount')"
  href="javascript:void(0)">+</A>
..........