JAVASCRIPT

Building `Drag-and-Drop` DIVs: Polishing the Look and Feel

This is the last tutorial of the series “Building drag-and-drop DIVs.” Welcome back. In three parts, this series introduces the key points for creating dragging DIV elements, for quick inclusion in web pages, emulating the behavior of many user interfaces found in current desktop applications.

Author Info:

By: Alejandro Gervasio

Poor Best

Rating:

/ 8

December 21, 2005

TABLE OF CONTENTS:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<title>DRAG-AND-DROP DOM-BASED WINDOWS</title>
<script type="text/javascript" src="path-to-
library/x_core.js"></script>
<script type="text/javascript" src="path-to-
library/x_event.js"></script>
<script type="text/javascript" src="path-to-
library/x_drag.js"></script>
<script type="text/javascript">
// create div element
function DOMDiv(x,y,w,h,col){
var div=document.createElement('div');
div.style.position='absolute';
div.style.left=x+'px';
div.style.top=y+'px';
div.style.width=w+'px';
div.style.height=h+'px';
div.style.backgroundColor=col;
div.style.padding='0';
return div
}
// create DOM window
function DOMWindow(x,y,w,h,title,content){
// create window structure
var winBody=new DOMDiv(x,y,w,h,'#ccc');
// assign ID attribute
winBody.setAttribute('id','domdiv');
winBody.style.border='2px outset #aaa';
winBody.style.cursor='default';
// create window title bar
var titleBar=new DOMDiv(4,4,w-14,18,'#00c');
titleBar.style.font='bold 10pt Arial';
titleBar.style.color='#fff';
titleBar.style.paddingLeft='4px';
// create window 'content area'
var contentArea=new DOMDiv(4,26,w-10,h-40,'#fff');
contentArea.style.width=document.all?(parseInt
(contentArea.style.width)-4)+'px':(parseInt
(contentArea.style.width)-7)+'px';
contentArea.style.border='1px inset #ccc';
contentArea.style.overflow='auto';
contentArea.style.padding='0px 2px 0px 4px';
contentArea.style.font='normal 10pt Arial';
// append title to title bar
titleBar.appendChild(document.createTextNode(title));
// append text to content area
contentArea.appendChild(document.createTextNode(content));
// append title bar
winBody.appendChild(titleBar);
// append content area
winBody.appendChild(contentArea);
// append window to document tree
document.getElementsByTagName('body')[0].appendChild(winBody);
}
// create 'domdiv' element and assign events
function initDomDiv(){
var domdiv=xGetElementById('domdiv');
xMoveTo(domdiv,100,100);
xEnableDrag(domdiv,domdivOnDragStart,domdivOnDrag);
xShow(domdiv);
}
function domdivOnDragStart(){}
// move 'domdiv' element
function domdivOnDrag(ele,mdx,mdy){
xMoveTo(ele,xLeft(ele)+mdx,xTop(ele)+mdy);
}
// display drag-and-drop div when page is loaded
window.onload=function(){
if(document.createElement&&document.
getElementById&&document.getElementsByTagName){
  // display 'domdiv'
    domWin=new DOMWindow(100,100,250,200,'Drag-and-drop DOM
Div','This dragging DIV element has been created with the DOM.');
  // make 'domdiv' a dragging element
  initDomDiv();
}
}
</script>
</head>
<body>
</body>
</html>

Bottom line

Before I wrap up this tutorial, a final note: the example I wrote earlier uses presentational JavaScript for styling each dragging DIV element, something that was discussed at the beginning of the article. However, you may want to utilize a CSS-based approach, in order to make your design stick a little closer to Web standards. The result will be nearly identical.

Now, it’s time to say goodbye. In this three-part series, I progressively went through the process for building drag-and-drop DIVs, ranging from writing a rather basic script to coding an advanced approach, by using the robust X library that Michael Foster allowed me to include in the corresponding examples. Thus, you have the knowledge and the tools for spicing up your web-based user interfaces utilizing true drag-and-drop DIVs. Wait are you waiting for? Go for it!

DISCLAIMER: The content provided in this article is not warranted or guaranteed by Developer Shed, Inc. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. As such it is incumbent upon the reader to employ real-world tactics for security and implementation of best practices. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. If this is a hardware review, it is not recommended to open and/or modify your hardware.