Reprinted from the following blog https://blog.csdn.net/jian_xi/article/details/77595209
BACKGROUND: Recently found a suitable label will appear after clicking a shadow doing a mobile terminal project. And this did not happen in the pc. After the review found that adding a single line of code.
-webkit-tap-highlight-color: rgba(0,0,0,0);
There are said to be online to see the reasons outline, followed by plus and there is no effect, so the judge with the outline does not matter.