This article describes the method of implementing the keyboard to control DIV movement by js. Share it for your reference. The specific analysis is as follows:
CSS Style Part:
Copy the code as follows: <style type="text/css">
html,body{overflow:hidden;}
body{margin:0;padding:0;}
pre{color:green;padding:10px 15px;background:#f0f0f0;border:1px dotted #333;font:12px/1.5 Courier New;margin:12px;}
span{color:#999;}
#box{position:absolute;top:50px;left:300px;width:100px;height:100px;background:red;}
</style>
js part:
Copy the code as follows:<script type="text/javascript">
window.onload = function ()
{
var oBox = document.getElementById("box");
var bLeft = bTop = bRight = bBottom = bCtrlKey = false;
setInterval(function ()
{
if (bLeft)
{
oBox.style.left = oBox.offsetLeft - 10 + "px"
}
else if (bRight)
{
oBox.style.left = oBox.offsetLeft + 10 + "px"
}
if (bTop)
{
oBox.style.top = oBox.offsetTop - 10 + "px"
}
else if(bBottom)
{
oBox.style.top = oBox.offsetTop + 10 + "px"
}
//Prevent overflow
limit();
},30);
document.onkeydown = function (event)
{
var event = event || window.event;
bCtrlKey = event.ctrlKey;
switch (event.keyCode)
{
case 37:
bLeft = true;
break;
case 38:
if(bCtrlKey)
{
var oldWidth = oBox.offsetWidth;
var oldHeight = oBox.offsetHeight;
oBox.style.width = oBox.offsetWidth * 1.5 + "px";
oBox.style.height = oBox.offsetHeight * 1.5 + "px";
oBox.style.left = oBox.offsetLeft - (oBox.offsetWidth - oldWidth) / 2 + "px";
oBox.style.top = oBox.offsetTop - (oBox.offsetHeight - oldHeight) / 2 + "px";
break;
}
bTop = true;
break;
case 39:
bRight = true;
break;
case 40:
if(bCtrlKey)
{
var oldWidth = oBox.offsetWidth;
var oldHeight = oBox.offsetHeight;
oBox.style.width = oBox.offsetWidth * 0.75 + "px";
oBox.style.height = oBox.offsetHeight * 0.75 + "px";
oBox.style.left = oBox.offsetLeft - (oBox.offsetWidth - oldWidth) / 2 + "px";
oBox.style.top = oBox.offsetTop - (oBox.offsetHeight - oldHeight) / 2 + "px";
break;
}
bBottom = true;
break;
case 49:
bCtrlKey && (oBox.style.background = "green");
break;
case 50:
bCtrlKey && (oBox.style.background = "yellow");
break;
case 51:
bCtrlKey && (oBox.style.background = "blue");
break;
}
return false
};
document.onkeyup = function (event)
{
switch ((event || window.event).keyCode)
{
case 37:
bLeft = false;
break;
case 38:
bTop = false;
break;
case 39:
bRight = false;
break;
case 40:
bBottom = false;
break;
}
};
//Prevent overflow
function limit()
{
var doc = [document.documentElement.clientWidth, document.documentElement.clientHeight]
//Prevent the left side from overflow
oBox.offsetLeft <=0 && (oBox.style.left = 0);
//Prevent top overflow
oBox.offsetTop <=0 && (oBox.style.top = 0);
//Prevent the right side from overflow
doc[0] - oBox.offsetLeft - oBox.offsetWidth <= 0 && (oBox.style.left = doc[0] - oBox.offsetWidth + "px");
//Prevent bottom overflow
doc[1] - oBox.offsetTop - oBox.offsetHeight <= 0 && (oBox.style.top = doc[1] - oBox.offsetHeight + "px")
}
};
</script>
illustrate:
Top: ↑ Next: ↓ Left: ← Right: →
Ctrl + 1: The background turns green
Ctrl + 2: The background turns yellow
Ctrl + 3: The background changes to blue
Ctrl + ↑: Zoom in
Ctrl + ↓ : Shrink
html part:
The code copy is as follows: the block being moved [DIV]
<div id="box"></div>
I hope this article will be helpful to everyone's JavaScript programming.