Determine whether two rectangles intersect the algorithm

The spatial position of two rectangles (2d) has four cases, as shown in the following figure:

To the two rectangle named a, a, but two rectangular sitting and lower-right coordinate (ax0,ay0), (bx0,by0), according to the judgment of four cases intersect there are four cases, that is, to write four judgments, this is a bit wordy, in fact, according to the four kinds of circumstances can be introduced by the law, as shown below:

This algorithm can be written as

Bx1>ax0,by1>ay1,ax1>bx0,ay1>by0

Here is a JS write example, of course, others, take over to do the proof:

<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "Http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd "> The results shown are: