How to implement shopping cart checkout with JavaScript

JavaScript method to implement shopping cart settlement: 1. Execute the function after the page is loaded; 2. Get the element; 3. Set the plus and minus buttons; 4. Save the subscript; 5. Set the click event of the plus and minus signs ; 6. Create a state change event for the check box.

The operating environment of this article: windows7 system, javascript version 1.8.5, Dell G3 computer.

How to implement shopping cart settlement with JavaScript?

HTML code:

 
 
  - 
 0件 
 + 
 10元 
 
 小计:  
 
 
  - 
 0件 
 + 
 20元 
 
 小计:  
 
 
  - 
 0件 
 + 
 30元 
 
 小计:  
 
 
  - 
 0件 
 + 
 40元 
 
 小计:  
 
 
  - 
 0件 
 + 
 50元 
 
 小计:  
 
 
 
  全选  
 商品总计: 0 
 
 商品总价: 0 
 
 
 CSS代码： html,body,ul,p { margin:0; padding:0; } ul,li { list-style:none; } ul { width:450px; } li { display:flex; justify-content:space-around; } .sum { width:450px; display:flex; justify-content:space-around; } #container { width:450px; margin:100px auto; }

JS code:

// 1.页面加载后执行 window.onload = function() { // 2.获取元素 var liCheck = document.getElementsByName("liCheck"); //li里面的复选框 var decrease = document.getElementsByClassName("decrease"); //减号 var piece = document.getElementsByClassName("piece"); //件数 var increase = document.getElementsByClassName("increase"); //加号 var price = document.getElementsByClassName("price"); //单价 var smallPrice = document.getElementsByClassName("smallPrice"); //小计 var checkAll = document.getElementById("checkAll"); //全选复选框 var totalCount = document.getElementById("totalCount"); //总计 var totalPrice = document.getElementById("totalPrice"); //总价 // 3.加减按钮 for (var i = 0; i < decrease.length; i++) { // 4.另存下标 decrease[i].index = i; increase[i].index = i; liCheck[i].index = i; // 5.减号的点击事件 decrease[i].onclick = function() { // 5-1.判断件数是否大于0 if (piece[this.index].innerHTML <= 1) { this.disabled = true; //当件数小于等于0时, 将减号按钮禁用 } // 5-1-1.当前件数-1 piece[this.index].innerHTML--; // 5-1-2.计算小计 smallPrice[this.index].value = Number(smallPrice[this.index].value) - Number(price[this.index].innerHTML); // 6-4.如果当前条目是被选中状态, 则需要将该商品计入总计和总价 if (liCheck[this.index].checked) { //选中 totalCount.innerHTML--; totalPrice.innerHTML = Number(totalPrice.innerHTML) - Number(price[this.index].innerHTML); } } // 6.加号的点击事件 increase[i].onclick = function() { // 6-1.将对应的减号解禁 decrease[this.index].disabled = false; // 6-2.当前件数+1 piece[this.index].innerHTML++; // 6-3.计算小计 smallPrice[this.index].value = Number(smallPrice[this.index].value) + Number(price[this.index].innerHTML); // 6-4.如果当前条目是被选中状态, 则需要将该商品计入总计和总价 if (liCheck[this.index].checked) { //选中 totalCount.innerHTML++; totalPrice.innerHTML = Number(totalPrice.innerHTML) + Number(price[this.index].innerHTML); } } // 7.复选框的状态改变事件 var count = 0; //存储选中个数 liCheck[i].onchange = function() { // 7-1.判断是否选中 if (this.checked) { //选中状态 count++; totalCount.innerHTML = Number(totalCount.innerHTML) + Number(piece[this.index].innerHTML); //总计加当前件数 totalPrice.innerHTML = Number(totalPrice.innerHTML) + Number(smallPrice[this.index].value); //总计加当前件数 // 7-1-1. 判断选中个数是否与复选框个数一致 } else { //取消选中状态 count--; totalCount.innerHTML = Number(totalCount.innerHTML) - Number(piece[this.index].innerHTML); //总计加当前件数 totalPrice.innerHTML = Number(totalPrice.innerHTML) - Number(smallPrice[this.index].value); //总计加当前件数 } count == liCheck.length ? checkAll.checked = true : checkAll.checked = false; } } // 8.全选复选框 checkAll.onchange = function() { totalCount.innerHTML = 0; //总计置为0 totalPrice.innerHTML = 0; //总价置为0 for (var j = 0; j < liCheck.length; j++) { // 8-1. 将li里面的复选框与全选状态保持一致 liCheck[j].checked = this.checked; // 8-2. 判断是否全选 if (this.checked) { count = liCheck.length; totalCount.innerHTML = Number(totalCount.innerHTML) + Number(piece[j].innerHTML); totalPrice.innerHTML = Number(totalPrice.innerHTML) + Number(smallPrice[j].value); } else { count = 0; } } } }

Recommended study: "javascript Advanced Tutorial"

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