javascript下用键盘控制层的移动的代码
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>键盘控制层的移动</title>
<style type="text/css">
<!--
#Div {
position:absolute;
width:238px;
height:135px;
left:expression((body.clientWidth - this.offsetWidth)/2);
top:expression((body.clientHeight - this.offsetHeight)/2);
z-index:1;
text-align:center;
background:#AFDBFF;
border:#006699 1px solid;
}
#Txt{
font-size:9pt;
position:absolute;
width:200px;
top:expression((Div.offsetHeight - this.offsetHeight)/2);
left:expression((Div.offsetWidth - this.offsetWidth)/2);
}
#Txt p{
font-size:9pt;
margin:8px;
}
#Txt font{
color:#FF0000;
font-size:9pt;
}
#Layer1 {
border:#006699 1px solid;
padding:10px;
font-size:9pt;
color:#336699;
position:absolute;
top:expression((body.clientHeight - this.offsetHeight)/2);
left:expression((body.clientWidth - this.offsetWidth)/2 + Div.offsetWidth);
}
#Layer1 Input {
font-size:9pt;
color:#336699;
}
#Int {
text-align:right;
}
-->
</style>
</head>
<body>
<div id="Div"><span id="Txt"><p>请分别按下 <font>↑</font>、<font>↓</font>、<font>←</font>、<font>→</font>，</p><p>
试试看有什么效果？ </p></span></div>
<span id="Layer1">控制键设置:<br>
向上移动:
<input name="Up" type="text" value="↑" size="6"><br>
向下移动:
<input name="Down" type="text" value="↓" size="6"><br>
向左移动:
<input name="Left" type="text" value="←" size="6"><br>
向右移动:
<input name="Right" type="text" value="→" size="6"><br>
每次移动 <input name="Int" type="text" id="Int" value="5" size="4" maxlength="3">
px;</span>
</body>
</html>
<script language="javascript">
<!--
//alert(txt.style.top);
var up,down,left,right;
up = 38;
down = 40;
left = 37;
right = 39;
function document.onkeydown()
{
// alert(event.keyCode);
//左：37 上：38 右：39 下：40
var int;
int = parseInt(document.getElementById("Int").value);
if(int == "NaN")
int = 5;
var str = "",press,evet;
var div = document.getElementById("Div");
var txt = document.getElementById("Txt");
if(event.srcElement.tagName == "INPUT")
{
if(event.srcElement == document.getElementById("Int"))
{
if(event.keyCode == 13)
document.body.focus();
if((event.keyCode < 96 || event.keyCode > 105) && event.keyCode != 8 && event.keyCode != 46 && !(event.keyCode >= 37 && event.keyCode <= 40) )
event.returnValue = false;
return;
}
else
{
switch(event.keyCode)
{
case 37:{
event.srcElement.value = "←";
break;
}
case 38:{
event.srcElement.value = "↑";
break;
}
case 39:{
event.srcElement.value = "→";
break;
}
case 40:{
event.srcElement.value = "↓";
break;
}
}
switch(event.srcElement)
{
case document.getElementById("Up"):{
up = event.keyCode;
break;
}
case document.getElementById("Down"):{
down = event.keyCode;
break;
}
case document.getElementById("Left"):{
left = event.keyCode;
break;
}
case document.getElementById("Right"):{
right = event.keyCode;
break;
}
}
}
}
else
{
switch(event.keyCode)
{
case left:{
press = "<font> ← </font>";
evet = "<font>向 <b>左</b> 移动</font>" + " " + int + " px 。";
div.style.left = (parseInt(div.currentStyle.left) - int) + "px";
if(parseInt(div.style.left) <= 0)
{
evet = "已经到了 <font>最左边</font> ，无法再 <font>向左</font> 移动。";
div.style.left = "0px";
break ;
}
break;
}
case up:{
press = "<font> ↑ </font>";
evet = "<font>向 <b>上</b> 移动</font>" + " " + int + " px 。";
div.style.top = (parseInt(div.currentStyle.top) - int) + "px";
if(parseInt(div.style.top) <= 0)
{
evet = "已经到了 <font>最上边</font> ，无法再 <font>向上</font> 移动。";
div.style.top = "0px";
break ;
}
break;
}
case right:{
press = "<font> → </font>";
evet = "<font>向 <b>右</b> 移动</font>" + " " + int + " px 。";
div.style.left = (parseInt(div.currentStyle.left) + int) + "px";
if(parseInt(div.style.left) >= (parseInt(document.body.clientWidth) - parseInt(div.offsetWidth)))
{
div.style.left = parseInt(document.body.clientWidth) - parseInt(div.offsetWidth);
evet = "已经到了 <font>最右边</font> ，无法再 <font>向右</font> 移动。";
break ;
}
break;
}
case down:{
press = "<font> ↓ </font>";
evet = "<font>向 <b>下</b> 移动</font>" + " " + int + " px 。";
div.style.top = (parseInt(div.currentStyle.top) + int) + "px";
if(parseInt(div.style.top) >= (parseInt(document.body.clientHeight) - parseInt(div.offsetHeight)))
{
div.style.top = parseInt(document.body.clientHeight) - parseInt(div.offsetHeight);
evet = "已经到了 <font>最下边</font> ，无法再 <font>向下</font> 移动。";
break ;
}
break;
}
default:
{
return;
}
}
str = "<p>您按下了" + press + "键，</p>";
str += "<p>该图层" + evet;
txt.innerHTML = str;
}
}
//-->
</script>
[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]
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