onmousedown活用之碰撞效果

通过绝对定位,在页面中随意位置设置两个div;

也就是说div 是拖动的框,div1和div2是被触碰的框;

 1 <!DOCTYPE html>
 2 <html>
 3 
 4 <head>
 5     <meta charset="UTF-8">
 6     <title></title>
 7     <style type="text/css">
 8         #div {
 9             width: 100px;
10             height: 100px;
11             background: pink;
12             position: absolute;
13             top: 50px;
14             left: 60px;
15             cursor: pointer;
16         }
17         
18         #div1 {
19             width: 100px;
20             height: 100px;
21             border: 1px solid black;
22             position: absolute;
23             top: 300px;
24             left: 100px;
25         }
26         
27         #div2 {
28             width: 100px;
29             height: 100px;
30             border: 1px solid blue;
31             position: absolute;
32             top: 200px;
33             left: 600px;
34         }
35     </style>
36 </head>
37 
38 <body>
39     <div id="div"></div>
40     <div id="div1"></div>
41     <div id="div2"></div>
42     
43 </body>
44 
45 </html>

所有的script是在写在body里面的，

 1 <script type="text/javascript">
 2         var Div = document.getElementById("div");
 3         var Div1 = document.getElementById("div1");
 4         var Div2 = document.getElementById("div2");
 5 
 6         //第一个固定框的上下左右的值
 7         var top1 = parseInt(getStyle(div1, "top"));
 8         var bottom1 = parseInt(getStyle(div1, "top")) + 100;
 9         var left1 = parseInt(getStyle(div1, "left"));
10         var right1 = parseInt(getStyle(div1, "left")) + 100;
11 
12         //第二个固定框的上下左右的值
13         var top2 = parseInt(getStyle(div2, "top"));
14         var bottom2 = parseInt(getStyle(div2, "top")) + 100;
15         var left2 = parseInt(getStyle(div2, "left"));
16         var right2 = parseInt(getStyle(div2, "left")) + 100;
17         //alert(top1);
18         var red1 = "blue";
19         var red2 = "red";
20 
21         Div.onmousedown = function(ev) {
22             var o = event || ev;
23             //获取到鼠标点击的位置距离div左侧和顶部边框的距离
24             oX = o.clientX - parseInt(getStyle(Div, "left"));
25             oY = o.clientY - parseInt(getStyle(Div, "top"));
26             //当鼠标移动，把鼠标的偏移量给div
27             document.onmousemove = function(ev) {
28                 var o = event || ev;
29                 //计算出鼠标在XY方向上移动的偏移量，把这个偏移量加给DIV的左边距和上边距，div就会跟着移动
30                 Div.style.left = o.clientX - oX + "px";
31                 Div.style.top = o.clientY - oY + "px";
32 
33                 var left = parseInt(getStyle(div, "left"));
34                 var right = parseInt(getStyle(div, "left")) + 100;
35                 var top = parseInt(getStyle(div, "top"));
36                 var bottom = parseInt(getStyle(div, "top")) + 100;
37 
38 
39                 //第鼠标框的bottom值小于第二个框的top1值
40                 //第鼠标框的left值大于第二个框的right1值
41                 //第鼠标框的top值大于第二个框的bottom1值
42                 //第鼠标框的right值小于第二个框的left1值
43                 //当这些都满足的时候，说明第鼠标框没有触碰第二个框，所以背景色不变
44                 //否则，就是触动框了，背景色变
45                 if (bottom < top1 || left > right1 || top > bottom1 || right < left1) {
46                     Div1.style.background = "";
47                 } else {
48                     Div1.style.background = red1;
49                 }
50 
51                 if (bottom < top2 || left > right2 || top > bottom2 || right < left2) {
52                     Div2.style.background = "";
53                 } else {
54                     Div2.style.background = red2;
55                 }
56 
57             }
58 
59 
60             //当鼠标按键抬起，清除移动事件
61             document.onmouseup = function() {
62                 document.onmousedown = null;
63                 document.onmousemove = null;
64             }
65 
66         }
67 
68         //获取属性的数值
69         function getStyle(obj, attr) {
70             if (obj.currentStyle) {
71                 //currentStyle获取样式的值，对应的是ie浏览器
72                 return obj.currentStyle[attr];
73             } else {
74                 //同理，对应的是其他浏览器
75                 return getComputedStyle(obj, false)[attr];
76             }
77         }
78     </script>

 

posted @ 2016-11-22 14:08  rookieM  阅读(348)  评论(0)  编辑  收藏  举报