在测试用鼠标点击按钮,使图片左右上下移动:
效果如下:
代码如下:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> <style type="text/css"> div{ width: 600px; height: 400px; margin: 100px auto 0; background: pink; position: relative; } img{ width: 60px; height: 60px; position: absolute; top: 0px; left: 0px; } table{ width: 120px; height: 120px; margin: 0 auto; } </style> <script> function move(num){ var mario = document.getElementById("mario"); var l = mario.style.left;//获取图片当前left值 var t = mario.style.top;//获取图片当前top值 l = Number(l.substr(0, l.length-2));//截取left值,去掉px 如果改成parseInt()则会失效,详情继续往下看解决办法 t = Number(t.substr(0, t.length-2));//截取top值,去掉px switch(num){ case 0: mario.style.top = (t-10)+"px"; break; case 1: mario.style.left = (l+10)+"px"; break; case 2: mario.style.top = (t+10)+"px"; break; case 3: mario.style.left = (l-10)+"px"; break; } } </script> </head> <body> <div> <img src="img.jpg" id="mario" alt=""/> </div> <table> <tr> <th colspan="3">点击移动图片</th> </tr> <tr align="center"> <td colspan="3"><input type="button" value="↑" onclick="move(0)"></td> </tr> <tr> <td><input type="button" value="←" onclick="move(3)"></td> <td>㊣</td> <td><button onclick="move(1)">→</button></td> </tr> <tr align="center"> <td colspan="3"><input type="button" value="↓" onclick="move(2)"></td> </tr> </table> </body> </html>
在上面如果我们吧Number()改成parseInt() 我们会发现失效了,鼠标点击图片不会移动,反而会报错。
如果我们想换成parseInt()那我们可以这样改
把img图形的样式改为内联样式:
<img src="img.jpg" id="mario" alt="" style="position: absolute;top: 0px;left: 0px;"/>
这样再把l = Number(l.substr(0, l.length-2)); 改为l = parseInt(l.substr(0, l.length-2));就不会报错了
为什么会这样呢:
是因为style只能获取内联样式,所以使用parseInt就不能实现。
键盘控制图片移动:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> <style type="text/css"> div{ width: 600px; height: 400px; margin: 100px auto 0; background: pink; position: relative; } img{ width: 60px; height: 60px; position: absolute; top: 0px; left: 0px; } table{ width: 120px; height: 120px; margin: 0 auto; } </style> <script> window.onload = function () { document.onkeydown = function () { var event = event || window.event;//浏览器兼容问题 var mario = document.getElementById("mario"); var l = mario.style.left;//获取图片当前left值 var t = mario.style.top;//获取图片当前top值 l = Number(l.substr(0, l.length-2));//截取left值,去掉px t = Number(t.substr(0, t.length-2));//截取top值,去掉px switch(event.keyCode){ case 38: mario.style.top = (t-10)+"px"; break; case 39: mario.style.left = (l+10)+"px"; break; case 40: mario.style.top = (t+10)+"px"; break; case 37: mario.style.left = (l-10)+"px"; break; } } } function move(num){ } </script> </head> <body> <div> <img src="img.jpg" id="mario" alt=""/> </div> </body> </html>