zcy_dr高手.请帮下忙.
<img src="images/1111.jpg" width="500" height="300" usemap="#map_sample" border="0" /><map name="map_sample" id="map_sample"><area shape="poly" coords="284,47,270,88" href="#" /><area shape="poly" coords="340,164,304,123" href="#" /></map><script>function foo(pos1,pos2,pos3,pos4){var x,y; if(pos1.x==pos2.x && pos1.y != pos2.y){ if(pos3.x==pos4.x && pos3.y != pos4.y) return false; x = pos1.x; var k2 = (pos3.y-pos4.y)/(pos3.x-pos4.x); var b2 = pos3.y - k2*pos3.x; y = k2*x+b2; }else if(pos3.x==pos4.x && pos3.y != pos4.y){ x = pos3.x; var k1 = (pos1.y-pos2.y)/(pos1.x-pos2.x); var b1 = pos1.y - k1*pos1.x; y = k1*x+b1; }else{ var k1 = (pos1.y-pos2.y)/(pos1.x-pos2.x); var k2 = (pos3.y-pos4.y)/(pos3.x-pos4.x); if(k1 == k2){ return false; } var b1 = pos1.y - k1*pos1.x; var b2 = pos3.y - k2*pos3.x; x = (b2-b1)/(k1-k2); y = k1*x+b1; } if(((x<=pos1.x && x>=pos2.x) || (x<=pos2.x && x>=pos1.x)) && ((x<=pos3.x && x>=pos4.x) || (x<=pos4.x && x>=pos3.x))) return {x:x,y:y}; else return false;}//326,123,354,84var r = foo({x:284,y:47},{x:270,y:88},{x:340,y:164},{x:304,y:123});if(r) alert("交点为：x:"+r.x+",y:"+r.y);else alert("没有交点");</script>