Use js to solve the div width problem caused by the border attribute_javascript skills

Let's take a look at a routine

Pay attention to the comments. Why does this phenomenon occur? In fact, it is caused by the border, because ok.style.width specifies the width of the div, and offsetwidth refers to the actual width, including the border width. Therefore, the width value obtained by the formula on the right is actually one pixel larger than that on the left. The solution is to subtract 3 pixels each time to achieve the purpose of actually subtracting one pixel. Or use parseInt(div.style.width) on the right side, but modify the div as follows: