The fromElement attribute of the event object solves a bug in setting the primary object in the hot zone.

After you click the hyperlink "set as primary entity", the original prompt box will change color and the content will be displayed: "already set as merged primary entity ".
Problem: when there is another hot zone B under the hyperlink in the prompt box of a hot zone, clicking the hyperlink in the prompt box of a hot zone will trigger the mouseover event in the B hot zone, the prompt box in the hot zone disappears.
I had a hard time thinking about this problem and couldn't find a solution. Last week, Zhou Jun asked me to check the source element of the event. I suddenly thought that the IE event object had a property fromElement. After testing it, after clicking the hyperlink in the hotspot prompt box, the fromElement in the mouseover event in the B hotspot is null, in this way, in the function that displays the prompt box of the hot zone, you can determine whether a fromElement is null. If it is null, return. Now the problem is solved, although this fromElement only exists in the event of IE.