Javascript: When onmouseover and onmouseout are used, when you move the cursor over the child element of the element, the two events of the current element are also executed.

When JS uses onmouseover and onmouseout, when the mouse moves to the child element of the element, the two events of the current element will also be executed,
To solve this problem, add a judgment statement: If (Event. toelement)
{
If ( ! This . Contains (event. toelement ))
{
Alert ( ' OK ' );
}
}

toelement indicates the elements that move the mouse over.
here, this is the outermost element.
use this. contains (event. toelement), you can check whether the mouse moves to the element is the descendant element of the current element.