JavaScript development of shopping cart layout

First of all, we need to understand what kind of function we need to make

To make a simple shopping cart, the table has the unit price, the addition and subtraction of the quantity, and then there is a total price. When we click add or subtract, The total price will change

Let’s look at the following html layout code as follows:

      
  
 
 
名称
 
单价
 
数量
 
总价
 
 
 
手表
 
1999
 
 -  + 
 
1999
 
 
  

As shown in the above code, friends can see that there are plus and minus signs on both sides of the text box, and then friends can see The cell with id='td' has 1999 in it, which is the default value. The unit price

The cell with id="td2" is used to store the total price