<!doctype html> <html> <head> <meta charset="utf-8"> <title>无标题文档</title> <style> div{100px; height:100px; } #box{background:red; position:absolute; } #box1{background:green;position:absolute;top:300px; left:300px;} </style> <script> //两个碰撞的盒子。是建立在一个不动的基础上。所以可以根据不动的盒子求出四个方向的left和top值。然后再判断其是否碰撞，且碰撞的过程随时改变其层级，（原需 var 8个变量，现在只需4个变量） function collText(obj,left,top,obj1){ var l1=obj.offsetLeft-obj.offsetWidth; var t1=obj.offsetTop-obj.offsetHeight; var r1=obj.offsetLeft+obj.offsetWidth; var b1=obj.offsetTop+obj.offsetHeight; if(left<l1||top<t1||left>r1||top>b1){ obj.style.zIndex=3; obj1.style.zIndex=1; return true; }else{ obj.style.zIndex=1; obj1.style.zIndex=3; return false; } }; window.onload=function(){ var oBox=document.getElementById('box'); var oBox1=document.getElementById('box1'); oBox.onmousedown=function(ev){ var oEvent= ev || event; var disX=oEvent.clientX-oBox.offsetLeft; var disY=oEvent.clientY-oBox.offsetTop; document.onmousemove=function(ev){ var oEvent= ev || event; var l=oEvent.clientX-disX; var t=oEvent.clientY-disY; oBox.style.left=l+'px' ; oBox.style.top=t+'px' ; if(collText(oBox1,l,t,oBox)){ oBox1.style.background='green'; }else{ oBox1.style.background='yellow'; } }; document.onmouseup=function(){ document.onmousemove=null; document.onmouseup=null; oBox.reseaseCapture&&oBox.reseaseCapture(); }; oBox.setCapture&&oBox.setCapture(); return false; } oBox1.onmousedown=function(ev){ var oEvent= ev || event; var disX1=oEvent.clientX-oBox1.offsetLeft; var disY1=oEvent.clientY-oBox1.offsetTop; document.onmousemove=function(ev){ var oEvent= ev || event; var le=oEvent.clientX-disX1; var to=oEvent.clientY-disY1; oBox1.style.left=le+'px' ; oBox1.style.top=to+'px' ; if(collText(oBox,le,to,oBox1)){ oBox.style.background='red'; }else{ oBox.style.background='#000'; } }; document.onmouseup=function(){ document.onmousemove=null; document.onmouseup=null; oBox1.reseaseCapture&&oBox1.reseaseCapture(); } oBox1.setCapture&&oBox1.setCapture(); return false; } } </script> </head> <body> <div id="box"></div> <div id="box1"></div> </body> </html>