1. 实现兼容低版本IE的getElementsByClassName()方法
2. JS表格操作
3. 通过parseInt()，parseFloat()把字符串转换成数字
4. 通过toFixed()把数字格式化成指定位数的小数
5. 事件代理的运用
效果图：
border-collapse有两个值可以选择，分别是collapse和separate，就是合并边框和分离边框，分离边框之下又可以设置间距和边框样式
border-spacing:2em 4em;（设置右间距和下间距）
border-style:none solid dashed dotted;（分别设置上右下左的样式）
html结构：
1 <table id="cartTable"> 2 <thead> 3 <tr> 4 <th><label><input class="check-all check" type="checkbox"/> 全选</label></th> 5 <th>商品</th> 6 <th>单价</th> 7 <th>数量</th> 8 <th>小计</th> 9 <th>操作</th> 10 </tr> 11 </thead> 12 <tbody> 13 <tr> 14 <td class="checkbox"><input class="check-one check" type="checkbox" /></td> 15 <td class="goods"><img src="images/1.jpg" alt="" /><span>Casio/卡西欧 EX-TR350</span></td> 16 <td class="price">5999.88</td> 17 <td class="count"><span class="reduce"></span><input class="count-input" type="text" value="1"/><span class="add">+</span></td> 18 <td class="subtotal">5999.88</td> 19 <td class="operation"><span class="delete">删除</span></td> 20 </tr> 21 <tr> 22 <td class="checkbox"><input class="check-one check" type="checkbox" /></td> 23 <td class="goods"><img src="images/2.jpg" alt="" /><span>Canon/佳能 PowerShot SX50 HS</span></td> 24 <td class="price">3888.50</td> 25 <td class="count"><span class="reduce"></span><input class="count-input" type="text" value="1"/><span class="add">+</span></td> 26 <td class="subtotal">3888.50</td> 27 <td class="operation"><span class="delete">删除</span></td> 28 </tr> 29 <tr> 30 <td class="checkbox"><input class="check-one check" type="checkbox" /></td> 31 <td class="goods"><img src="images/3.jpg" alt="" /><span>Sony/索尼 DSC-WX300</span></td> 32 <td class="price">1428.50</td> 33 <td class="count"><span class="reduce"></span><input class="count-input" type="text" value="1"/><span class="add">+</span></td> 34 <td class="subtotal">1428.50</td> 35 <td class="operation"><span class="delete">删除</span></td> 36 </tr> 37 <tr> 38 <td class="checkbox"><input class="check-one check" type="checkbox" /></td> 39 <td class="goods"><img src="images/4.jpg" alt="" /><span>Fujifilm/富士 instax mini 25</span></td> 40 <td class="price">640.60</td> 41 <td class="count"><span class="reduce"></span><input class="count-input" type="text" value="1"/><span class="add">+</span></td> 42 <td class="subtotal">640.60</td> 43 <td class="operation"><span class="delete">删除</span></td> 44 </tr> 45 </tbody> 46 </table> 47 <div class="foot" id="foot"> 48 <label class=" fl select-all"><input type="checkbox" class="check-all check" /> 全选</label> 49 <a class="fl delete" id="deleteAll" href="javascript:;">删除</a> 50 <div class="fr closing">结 算</div> 51 <div class="fr total">合计：￥<span id="priceTotal">0.00</span></div> 52 <div class="fr select" id="selected">已选商品<span id="selectedTotal">0</span>件<span class="arrow up">︽</span><span class="arrow down">︾</span></div> 53 <div class="selected-view"> 54 <div id="selectedViewList" class="clearfix"> 55 <div><img src="images/1.jpg"><span>取消选择</span></div> 56 </div> 57 <span class="arrow">◆<span>◆</span></span> 58 </div> 59 </div>
css代码：
1 *{
2 margin: 0;
3 padding: 0;
4 }
5 a{
6 color: #666;
7 text-decoration: none;
8 }
9 body{
10 padding:20px;
11 color: #666;
12 }
13 .fl{
14 float: left;
15 }
16 .fr{
17 float: right;
18 }
19 table{
20 border-collapse: collapse;
21 border-spacing: 0;
22 border: 0;
23 text-align: center;
24 937px;
25 }
26 th,td{
27 border: 1px solid #cadeff;
28 }
29 th{
30 background: #e2f2ff;
31 border-top: 3px solid #a7cbff;
32 height: 30px;
33 }
34 td{
35 padding: 10px;
36 color: #444;
37 }
38 tbody tr:hover{
39 background: RGB(238,246,255);
40 }
41 .checkbox{ 60px;}
42 .goods{ 300px;}
43 .goods span{
44 180px;
45 margin-top: 20px;
46 text-align: left;
47 float: left;
48 }
49 .price{ 130px;}
50 .count{ 90px;}
51 .count .add, .count input, .count .reduce{
52 float: left;
53 margin-left: -1px;
54 position: relative;
55 z-index: 0;
56 }
57 .count .add, .count .reduce{
58 height: 23px;
59 17px;
60 border: 1px solid #e5e5e5;
61 background: #f0f0f0;
62 text-align: center;
63 line-height: 23px;
64 color: #444;
65 }
66 .count .add:hover, .count .reduce:hover{
67 color: #f50;
68 z-index: 3;
69 border-color: #f60;
70 cursor: pointer;
71 }
72 .count input{
73 50px;
74 height: 15px;
75 line-height: 15px;
76 border: 1px solid #aaa;
77 color: #343434;
78 text-align: center;
79 padding: 4px 0;
80 background-color: #fff;
81 z-index: 2;
82 }
83 .subtotal{
84 150px;
85 color: red;
86 font-weight: bold;
87 }
88 .operation{ 80px;}
89 .operation span:hover, .a:hover{
90 cursor: pointer;
91 color: red;
92 text-decoration: underline;
93 }
94 img{
95 100px;
96 height: 80px;
97 margin-right: 10px;
98 float: left;
99 }
100 .foot{
101 935px;
102 margin-top: 10px;
103 color: #666;
104 height: 48px;
105 border: 1px solid #c8c8c8;
106 background-image: linear-gradient(RGB(241,241,241),RGB(226,226,226));
107 position: relative;
108 z-index: 8;
109 }
110 .foot div, .foot a{
111 line-height: 48px;
112 height: 48px;
113 }
114 .foot .select-all{
115 100px;
116 height: 48px;
117 line-height: 48px;
118 padding-left: 5px;
119 color: #666;
120 }
121 .foot .closing{
122 border-left: 1px solid #c8c8c8;
123 100px;
124 text-align: center;
125 color: #000;
126 font-weight: bold;
127 background: RGB(238,238,238);
128 cursor: pointer;
129 }
130 .foot .total{
131 margin: 0 20px;
132 cursor: pointer;
133 }
134 .foot #priceTotal, .foot #selectedTotal{
135 color: red;
136 font-family: "微软雅黑";
137 font-weight: bold;
138 }
139 .foot .select{
140 cursor: pointer;
141 }
142 .foot .select .arrow{
143 position: relative;
144 top: -3px;
145 margin-left: 3px;
146 }
147 .foot .select .down{
148 position: relative;
149 top: 3px;
150 display: none;
151 }
152 .show .select .down{
153 display: inline;
154 }
155 .show .select .up{
156 display: none;
157 }
158 .foot .select:hover .arrow{
159 color: red;
160 }
161 .foot .selected-view{
162 935px;
163 border: 1px solid #c8c8c8;
164 position: absolute;
165 height: auto;
166 background: #fff;
167 z-index: 9;
168 bottom: 48px;
169 left: -1px;
170 display: none;
171 }
172 .show .selected-view{display: block;}
173 .foot .selected-view div{height: auto;}
174 .foot .selected-view .arrow{
175 font-size: 16px;
176 line-height: 100%;
177 color: #c8c8c8;
178 position: absolute;
179 right: 330px;
180 bottom: -9px;
181 }
182 .foot .selected-view .arrow span{
183 color: #fff;
184 position: absolute;
185 left: 0;
186 bottom: 1px;
187 }
188 #selectedViewList{
189 padding: 20px;
190 margin-bottom: -20px;
191 }
192 #selectedViewList div{
193 display: inline-block;
194 position: relative;
195 100px;
196 height: 80px;
197 border: 1px solid #ccc;
198 margin: 10px;
199 }
200 #selectedViewList div span{
201 display: none;
202 color: #fff;
203 font-size: 12px;
204 position: absolute;
205 top: 0;
206 right: 0;
207 60px;
208 height: 18px;
209 line-height: 18px;
210 text-align: center;
211 background: RGBA(0,0,0,.5);
212 cursor: pointer;
213 }
214 #selectedViewList div:hover span{
215 display: block;
216 }
js部分：
1）实现商品的全选功能及数量和价格的计算
1 var cartTable = document.getElementById('cartTable');
2 var tr = cartTable.children[1].rows;//获取table下的tbody下的每一行
3 var checkInputs = document.getElementsByClassName('check');
4 var checkAllInputs = document.getElementsByClassName('check-all');
5 var selectedTotal = document.getElementById('selectedTotal');
6 var priceTotal = document.getElementById('priceTotal');
7 //计算总数和价格
8 function getTotal(){
9 var selected = 0;
10 var price = 0;
11 for(var i=0;i < tr.length; i++){
12 if(tr[i].getElementsByTagName('input')[0].checked){
13 selected += parseInt(tr[i].getElementsByTagName('input')[1].value);
14 price += parseFloat(tr[i].cells[4].innerHTML);//cells属性为获得tr下面的td
15 }
16 }
17 selectedTotal.innerHTML = selected;
18 priceTotal.innerHTML = price.toFixed(2);//保留两位小数
19 }
20 for(var i=0;i<checkInputs.length;i++){
21 checkInputs[i].onclick = function(){
22 if(this.className === 'check-all check'){//如果点击的是全选按钮，则使所有按钮的状态和它相同
23 for(var j=0;j<checkInputs.length;j++){
24 checkInputs[j].checked = this.checked;
25 }
26 }
27 if(this.checked == false){//如果其中一个变为未选中状态，则使全选按钮取消选中
28 for(var i=0;i<checkAllInputs.length;i++){
29 checkAllInputs[i].checked = false;
30 }
31 }
32 getTotal();
33 }
34 }
2)点击已选商品实现商品预览浮层的功能
点击已选商品时会显示出已选择商品的列表
同时在getTotal()函数中增加新创建的div
js代码：
1 function getTotal(){
2 var selected = 0;
3 var price = 0;
4 var HTMLstr = '';
5 for(var i=0;i < tr.length; i++){
6 if(tr[i].getElementsByTagName('input')[0].checked){
7 tr[i].className = 'on';
8 selected += parseInt(tr[i].getElementsByTagName('input')[1].value);
9 price += parseFloat(tr[i].cells[4].innerHTML);//cells属性为获得tr下面的td
10 HTMLstr += '<div><img src="'+ tr[i].getElementsByTagName('img')[0].src + '"><span>取消选择</span></div>';
11 }
12 else{
13 tr[i].className = '';
14 }
15 }
16 selectedTotal.innerHTML = selected;
17 priceTotal.innerHTML = price.toFixed(2);//保留两位小数
18 selectedViewList.innerHTML = HTMLstr;
19 if(selected == 0){
20 foot.className = 'foot';
21 }
22 }
23 for(var i=0;i<checkInputs.length;i++){
24 checkInputs[i].onclick = function(){
25 if(this.className === 'check-all check'){//如果点击的是全选按钮，则使所有按钮的状态和它相同
26 for(var j=0;j<checkInputs.length;j++){
27 checkInputs[j].checked = this.checked;
28 }
29 }
30 if(this.checked == false){//如果其中一个变为未选中状态，则使全选按钮取消选中
31 for(var i=0;i<checkAllInputs.length;i++){
32 checkAllInputs[i].checked = false;
33 }
34 }
35 getTotal();
36 }
37 }
38
39 selected.onclick = function(){
40 if(foot.className == 'foot'){
41 if(selectedTotal.innerHTML != 0){
42 foot.className = 'foot show';
43 }
44 }else{
45 foot.className = 'foot';
46 }
47 }
3)商品列表中的取消选择与事件代理
已选商品列表中没有appendChild的时候div和span都不存在，所以要使用事件代理。
1 selectedViewList.onclick = function(e){
2 var el = e.srcElement;
3 if(el.className == 'del'){
4 var index = el.getAttribute('index');
5 var input = tr[index].getElementsByTagName('input')[0];
6 input.checked = false;
7 input.onclick();
8 }
9 }
4）实现增减商品数量及小计价格的计算
1 //增减商品数量事件代理
2 for(var i=0;i<tr.length;i++){
3 tr[i].onclick = function(e){
4 e = e|| window.event;
5 var el = e.srcElement;
6 var cls = el.className;
7 var input = this.getElementsByTagName('input')[1];
8 var val = parseInt(input.value);
9 var reduce = this.getElementsByTagName('span')[1];
10 switch (cls){
11 case 'add':
12 input.value = val + 1;
13 reduce.innerHTML = '-';
14 getsubTotal(this);
15 break;
16 case 'reduce':
17 if(val > 1){
18 input.value = val - 1;
19 getsubTotal(this);
20 }else{
21 reduce.innerHTML = '';
22 }
23 }
24 getTotal();
25 }
26 tr[i].getElementsByTagName('input')[1].onkeyup = function(){
27 var val = parseInt(this.value);
28 var tr = this.parentNode.parentNode;//this指的是当前的input，其父节点的父节点就是当前的tr
29 var reduce = tr.getElementsByTagName('span')[1];
30 if(isNaN(val) || val < 1){
31 val = 1;
32 }
33 this.value = val;//保证输入框中都是大于1的纯数字
34 if(val <= 1){
35 reduce.innerHTML = '';
36 }
37 else{
38 reduce.innerHTML = '-';
39 }
40 getsubTotal(tr);
41 getTotal();
42 }
43 }
5）实现删除商品功能
学会用for循环删除数组中的一些数据时要回置下标 i 。
1 //删除商品
2 deleteAll.onclick = function(){
3 if(selectedTotal.innerHTML != '0'){
4 var conf = confirm("确定要删除所选商品吗");
5 if(conf){
6 for(var i=0;i<tr.length;i++){
7 var input = tr[i].getElementsByTagName('input')[0];
8 if(input.checked){
9 tr[i].parentNode.removeChild(tr[i]);
10 i --;//因为删除数组中的一个后，后面的索引就会向前移，此时要让i也向前移一个，回置下标i
11 }
12 }
13 getTotal();
14 }
15 }
16 }