js 购物车数量增减，总价格联动变化

前端JS实现购物车功能，点击商品加减按钮商品数量加减，点击单选按钮和全选按钮颜色变化，总价联动变化。项目中应用的都是bootstrap的样式，css就不一一贴出来了。

加函数，减函数，手动修改数量判断库存函数，总价格计算函数，单选事件，全选事件，一共分为6个事件

<div class="orderwrap"><div class="ordertouch clearfix"><div class="ordercont"><div class="orderitem clearfix" priceOne><div class="col-xs-1 clearPadding"></div><div class="col-xs-3 clearPadding"><a href=""><img src="" alt="" class="img-responsive"></a></div><div class="col-xs-7 clearPadding pl10"><div class="proname"><a href="">原味手剥大瓜子</a></div><div class="prodetail"><span class="font14 color-orange">￥<strong class="unitprice" unitprice>9.9</strong></span><span class="pro_oriprice"><del>19.9</del></span>  <span class="color82 font12">库存：100</span></div><div class="pronum"><div class="pull-left input-group"><div class="num">数量：</div><div class="btn-add omin" onclick="minus(this,'9.9','100');" style="padding:2px 8px;"><span class="glyphicon glyphicon-minus"></span></div><input type="text" class="btn-num onum" value="" name='count' onblur='amount_input(this,"9.9","100")' ><div class="btn-add oplus" onclick="plus(this,'9.9}','100}');" style="padding:2px 8px;"><span class="glyphicon glyphicon-plus"></span></div></div></div></div><div class="col-xs-1 clearPadding"></div><i class="iconfont o-label op-label checkitem" productid='}'></i><a href=""><div class="o-more"></div></a></div></div><div class="btn-del" onclick="btndel('',this)">删 除</div></div></div><div class="bottoms checkoutbox"><div class="col-xs-8  bordertop borderbottom"><div class="pull-left"><i class="o-label checkall iconfont" id="checkall"></i><span class="qxposition">全选</span></div><div class="pull-right"><div class="">合计： ￥ <span class="font14 color-orange allprice" id="allprice">0</span></div><div class="font12">不含运费</div></div></div><div class="col-xs-4 clearPadding"><button class="btn-checkout" onclick="sbm();">结算（<span class="allnum" id="amount">0</span>）</button></div></div>

//计算总价function setTotal(){var allprice=0;//总价格var allnum=0;//总数量$(".checkitem").each(function(){if($(this).hasClass('oncheck')){var num=parseInt($(this).parents('[priceOne]').find('input[name=count]').val());//单个商品的购买数量var price=$(this).parents('[priceOne]').find('[unitprice]').text();//商品单价需要从后台获取allprice+=num*price;//每样商品的总价allnum+=num;}})$(".allprice").html(allprice.toFixed(2));$(".allnum").html(allnum);}setTotal();

//手动修改文本框商品数量与库存的限制function amount_input(tag,sellprice,stock){var amount=parseInt($(tag).val());if(isNaN(amount)){layer.msg('最少购买量为1');$(tag).val(1);}else{if(amount>stock){layer.msg('购买数量不能大于库存');$(tag).val(stock);}else if(amount<1){layer.msg('最少购买量为1');$(tag).val(1);}}var val=parseFloat(sellprice)*parseInt($(tag).val());setTotal();}// 全选$('#checkall').click(function(){$(this).toggleClass('oncheck');if($(this).hasClass('oncheck')){$('.checkitem').addClass('oncheck');setTotal();}else{$('.checkitem').removeClass('oncheck');setTotal();}});//单选$('.checkitem').click(function(){$(this).toggleClass('oncheck');var itemsleng=$('.checkitem').length;var checkedleng=$('[priceOne]').find('i').filter('.oncheck').length;if(checkedleng==itemsleng){$('.checkall').addClass('oncheck');setTotal();}else{$('.checkall').removeClass('oncheck');setTotal();}});// 购买数量加function plus(tag,sellprice,stock){var _this=$(tag);var input=_this.prev('input');if(_this.prev('input[disabled]').length>0){return;}var amount=parseInt(input.val());amount++;if(amount>stock){return layer.msg('购买数量不能大于库存');}else{input.val(amount);setTotal();}}// 购买数量减function minus(tag,sellprice,stock){var _this=$(tag);var input=_this.next('input');if(_this.next('input[disabled]').length>0){return;}var amount=parseInt(input.val());amount--;if(amount<=0){return layer.msg('购买数量不能小于1');}else{input.val(amount);setTotal();}}