[JS]
var DragHandler = {
// private property.
_oElem : null,
// public method. Attach drag handler to an element.
attach : function(oElem) {
oElem.onmousedown = DragHandler._dragBegin;
// callbacks
oElem.dragBegin = new Function();
oElem.drag = new Function();
oElem.dragEnd = new Function();
return oElem;
},
// private method. Begin drag process.
_dragBegin : function(e) {
var oElem = DragHandler._oElem = this;
if (isNaN(parseInt(oElem.style.left))) { oElem.style.left = '0px'; }
if (isNaN(parseInt(oElem.style.top))) { oElem.style.top = '0px'; }
var x = parseInt(oElem.style.left);
var y = parseInt(oElem.style.top);
e = e ? e : window.event;
oElem.mouseX = e.clientX;
oElem.mouseY = e.clientY;
oElem.dragBegin(oElem, x, y);
document.onmousemove = DragHandler._drag;
document.onmouseup = DragHandler._dragEnd;
return false;
},
// private method. Drag (move) element.
_drag : function(e) {
var oElem = DragHandler._oElem;
var x = parseInt(oElem.style.left);
var y = parseInt(oElem.style.top);
e = e ? e : window.event;
oElem.style.left = x + (e.clientX - oElem.mouseX) + 'px';
oElem.style.top = y + (e.clientY - oElem.mouseY) + 'px';
oElem.mouseX = e.clientX;
oElem.mouseY = e.clientY;
oElem.drag(oElem, x, y);
return false;
},
// private method. Stop drag process.
_dragEnd : function() {
var oElem = DragHandler._oElem;
var x = parseInt(oElem.style.left);
var y = parseInt(oElem.style.top);
oElem.dragEnd(oElem, x, y);
document.onmousemove = null;
document.onmouseup = null;
DragHandler._oElem = null;
}
}
[HTML]
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>DEMO: Javascript drag handler</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link media="screen" type="text/css" rel="stylesheet" href="/demo/screen.css" />
<script type="text/javascript" src="webtoolkit.drag.js"></script>
</head>
<body>
<div id="container">
<div id="info">Start drag process...</div>
<div id="dragable1" style="position: relative; width: 50px; height: 50px; background: silver; border: 1px dashed red;"></div>
<div id="dragable2" style="position: relative; width: 60px; height: 60px; background: silver; border: 1px dashed red;"></div>
<div id="dragable3" style="position: relative; width: 70px; height: 70px; background: silver; border: 1px dashed red;"></div>
<script type="text/javascript">
function begin (element, x, y) {
var s = '#' + element.id + ' (begin drag)' + ' x:' + x + ', y:' + y;
updateInfo(s);
}
function drag (element, x, y) {
var s = '#' + element.id + ' (dragging)' + ' x:' + x + ', y:' + y;
updateInfo(s);
}
function end (element, x, y) {
var s = '#' + element.id + ' (end drag)' + ' x:' + x + ', y:' + y;
updateInfo(s);
}
function updateInfo(s) {
document.getElementById('info').innerHTML = s;
}
var dragable1 = DragHandler.attach(document.getElementById('dragable1'));
var dragable2 = DragHandler.attach(document.getElementById('dragable2'));
var dragable3 = DragHandler.attach(document.getElementById('dragable3'));
dragable1.dragBegin = begin;
dragable1.drag = drag;
dragable1.dragEnd = end;
dragable2.dragBegin = begin;
dragable2.drag = drag;
dragable2.dragEnd = end;
dragable3.dragBegin = begin;
dragable3.drag = drag;
dragable3.dragEnd = end;
</script>
</body>
</html>
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