I have adapted code from http://dunnbypaul.net/js_mouse/
I want to use a button to create new draggable divs but i keep getting error "is null or not an object"
heres the code - <html>
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<head>
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<title>Drag and drop module</title>
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<style type="text/css">
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#canvas {
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margin:auto;
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padding:0px;
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position: absolute;
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background-color:grey;
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border:dashed gray 1px;
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top: 5px;
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margin:auto;
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padding:0px;
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width:100%;
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height:400px;
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float:left;
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font-size: 8px;
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font-family:Arial, Helvetica, sans-serif;
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overflow: hidden;
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}
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#controls {
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margin:auto;
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padding:10px;
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position: absolute;
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width:100%;
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top:415px;
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float:left;
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background: grey;
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border:dashed black 1px;
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height: 150px;
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}
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#newObject {
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position: absolute;
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left: 10px;
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top: 10px;
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background-color:green;
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border:solid gray 1px;
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margin:10px;
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padding:4px;
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width:50px;
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height:50px;
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float:left;
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zIndex:1;
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cursor:pointer;
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font-size: 8px;
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font-family:Arial, Helvetica, sans-serif;
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}
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</style>
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<script type = "text/javascript">
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function createObject (){
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cv = document.getElementById("canvas");
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var newObject = document.createElement('div');
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newObject.Class = "newObject";
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newObject.id = "newObject";
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cv.appendChild(newObject);
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newObject.onmousedown=grab(this);
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}
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var mousex = 0;
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var mousey = 0;
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var grabx = 0;
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var graby = 0;
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var orix = 0;
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var oriy = 0;
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var elex = 0;
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var eley = 0;
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var algor = 0;
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var dragobj = null;
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function falsefunc() { return false; } // used to block cascading events
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function init()
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{
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document.onmousemove = update; // update(event) implied on NS, update(null) implied on IE
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update();
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}
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function getMouseXY(e) // works on IE6,FF,Moz,Opera7
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{
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if (!e) e = window.event; // works on IE, but not NS (we rely on NS passing us the event)
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if (e)
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{
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if (e.pageX || e.pageY)
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{ // this doesn't work on IE6!! (works on FF,Moz,Opera7)
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mousex = e.pageX;
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mousey = e.pageY;
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algor = '[e.pageX]';
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if (e.clientX || e.clientY) algor += ' [e.clientX] '
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}
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else if (e.clientX || e.clientY)
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{ // works on IE6,FF,Moz,Opera7
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mousex = e.clientX + document.body.scrollLeft;
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mousey = e.clientY + document.body.scrollTop;
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algor = '[e.clientX]';
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if (e.pageX || e.pageY) algor += ' [e.pageX] '
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}
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}
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}
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function update(e)
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{
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getMouseXY(e); // NS is passing (event), while IE is passing (null)
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document.getElementById('xpos').value = elex;
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document.getElementById('ypos').value = eley;
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document.getElementById('object').value = dragobj ? (dragobj.id ? dragobj.id : 'unnamed object') : '(null)';
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}
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function grab(context)
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{
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document.onmousedown = falsefunc; // in NS this prevents cascading of events, thus disabling text selection
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dragobj = context;
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dragobj.newObject.zIndex = 10; // move it to the top
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document.onmousemove = drag;
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document.onmouseup = drop;
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grabx = mousex;
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graby = mousey;
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elex = orix = dragobj.offsetLeft;
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eley = oriy = dragobj.offsetTop;
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update();
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}
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function drag(e) // parameter passing is important for NS family
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{
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if (dragobj)
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{
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elex = orix + (mousex-grabx);
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eley = oriy + (mousey-graby);
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dragobj.newObject.position = "absolute";
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dragobj.newObject.left = (elex).toString(10) + 'px';
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dragobj.newObject.top = (eley).toString(10) + 'px';
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}
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update(e);
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return false; // in IE this prevents cascading of events, thus text selection is disabled
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}
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function drop()
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{
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if (dragobj)
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{
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dragobj.style.zIndex = 0;
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dragobj = null;
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}
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update();
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document.onmousemove = update;
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document.onmouseup = null;
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document.onmousedown = null; // re-enables text selection on NS
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}
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</script>
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</head>
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<body onload="init();">
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<div id = "canvas">
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</div>
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<div id = "controls">
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<input type = "button" value = "New Object" onClick = "createObject()">
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<input type = "text" value = "" name = "xpos" id = "xpos">
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<input type = "text" value = "" name = "ypos" id = "ypos">
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<input type = "text" value = "" name = "object" id = "object">
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</div>
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</body>
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</html>
6  4943 
sorry just to be a little clearer.
Error:
Line: 116
Char: 3
error: 'dragobj.newObj ect' is null or not an object
code:0
acoder 16,027
Recognized Expert Moderator MVP
"If you can solve this your a genius!!" is a brilliant title :D, but doesn't really describe the problem, so I've changed it.
Re. your problem: dragobj.newObje ct is incorrect. Replace newObject with style. See if that makes a difference.
yeah I have already tried that. I think the problem lies in the createObject function. Seems to be a problem assigning the onmousedown event.
acoder 16,027
Recognized Expert Moderator MVP
Yeah, that should be: - newObject.onmousedown=function(){grab(this);}
Yeah, that should be:
- newObject.onmousedown=function(){grab(this);}
Has anyone every told you you're some pup! :)
Thanks... you don't know how much that has helped
acoder 16,027
Recognized Expert Moderator MVP Sign in to post your reply or Sign up for a free account.
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