• Markup-based: adding dojoType properties to HTML elements in the markup
• Programmatic: creating HTML elements in JavaScript

When using a toolkit such as dojo for layout rather than standard CSS, my preference would be to keep the dojo layout stuff entirely in JavaScript, separate from the markup, whilst still using HTML to describe my content. This allows an easy transition to/from dojo and CSS layout techniques, doesn’t clutter the markup with dojo specific stuff that would only be needed when JavaScript is enabled, and just provides a cleaner separation. I was sure this must be possible in dojo and it is; it just doesn’t seem to be well documented anywhere.

After playing for a while (and with quite a bit of help from James), I turned this…

<script type="text/javascript">
dojo.require("dijit.layout.BorderContainer");
dojo.require("dijit.layout.TabContainer");
dojo.require("dijit.layout.AccordionContainer");
dojo.require("dijit.layout.ContentPane");
</script>

<div dojoType="dijit.layout.BorderContainer"
  style="width: 100%; height: 100%;">
  <div dojoType="dijit.layout.ContentPane" region="top">
    Top pane
  </div>
  <div dojoType="dijit.layout.AccordionContainer" region="leading">
    <div dojoType="dijit.layout.AccordionPane" title="pane #1">
      accordion pane #1
    </div>
    <div dojoType="dijit.layout.AccordionPane" title="pane #2">
      accordion pane #2
    </div>
    <div dojoType="dijit.layout.AccordionPane" title="pane #3">
      accordion pane #3
    </div>
  </div>
  <div dojoType="dijit.layout.TabContainer" region="center">
    <div dojoType="dijit.layout.ContentPane" title="tab #1">
      tab pane #1
    </div>
    <div dojoType="dijit.layout.ContentPane" title="tab #2">
      tab pane #2
    </div>
    <div dojoType="dijit.layout.ContentPane" title="tab #3">
      tab pane #3
    </div>
  </div>
  <div dojoType="dijit.layout.ContentPane" region="trailing">
    Trailing pane
  </div>
  <div dojoType="dijit.layout.ContentPane" region="bottom">
    Bottom pane
  </div>
</div>

<style type="text/css">
 html, body {
 width: 100%;
 height: 100%;
 margin: 0;
 }
</style>

…into this…

<script type="text/javascript">
  dojo.require("dijit.layout.BorderContainer");
  dojo.require("dijit.layout.TabContainer");
  dojo.require("dijit.layout.AccordionContainer");
  dojo.require("dijit.layout.ContentPane");

  dojo.ready(function () {
    var mainContainer = new dijit.layout.BorderContainer(
      {}, 'mainContainer');
    var topPane = new dijit.layout.ContentPane(
      {'region': 'top'}, 'topPane');
    mainContainer.addChild(topPane);
    var leftPane = new dijit.layout.AccordionContainer(
      {'region': 'leading'}, 'leftPane');
    var accordionPane1 = new dijit.layout.AccordionPane(
      {'title': 'pane #1'}, 'accordionPane1');
    var accordionPane2 = new dijit.layout.AccordionPane(
      {'title': 'pane #2'}, 'accordionPane2');
    var accordionPane3 = new dijit.layout.AccordionPane(
      {'title': 'pane #3'}, 'accordionPane3');
    leftPane.addChild(accordionPane1);
    leftPane.addChild(accordionPane2);
    leftPane.addChild(accordionPane3);
    mainContainer.addChild(leftPane);
    var centerPane = new dijit.layout.TabContainer(
      {'region': 'center'}, 'centerPane');
    var tabPane1 = new dijit.layout.AccordionPane(
      {'title': 'tab #1'}, 'tabPane1');
    var tabPane2 = new dijit.layout.AccordionPane(
      {'title': 'tab #2'}, 'tabPane2');
    var tabPane3 = new dijit.layout.AccordionPane(
      {'title': 'tab #3'}, 'tabPane3');
    centerPane.addChild(tabPane1);
    centerPane.addChild(tabPane2);
    centerPane.addChild(tabPane3);
    mainContainer.addChild(centerPane);
    var rightPane = new dijit.layout.ContentPane(
      {'region': 'trailing'}, 'rightPane');
    mainContainer.addChild(rightPane);
    var bottomPane = new dijit.layout.ContentPane(
      {'region': 'bottom'}, 'bottomPane');
    mainContainer.addChild(bottomPane);
    mainContainer.startup();
  });
</script>

<div id="mainContainer">
  <div id="topPane">Top pane</div>
  <div id="leftPane">
    <div id="accordionPane1">accordion pane #1</div>
    <div id="accordionPane2">accordion pane #2</div>
    <div id="accordionPane3">accordion pane #3</div>
  </div>
  <div id="centerPane">
    <div id="tabPane1">tab pane #1</div>
    <div id="tabPane2">tab pane #2</div>
    <div id="tabPane3">tab pane #3</div>
  </div>
  <div id="rightPane">Trailing pane</div>
  <div id="bottomPane">Bottom pane</div>
</div>

<style type="text/css">
  html, body, #mainContainer {
    width: 100%;
    height: 100%;
    margin: 0;
  }
</style>

There’s lots of code but I prefer the separation. In reality I’d move the JavaScript etc into a separate files but it’s easier to demonstrate like this.

A couple of gotchas:

• Adding extra HTML elements dynamically
  Sometimes dojo will require extra divs for layout purposes (for different digit classes, e.g. dijit.layout.BorderContainer). Clearly it would be wrong to modify markup to include extra divs just for this so you’ll probably want to create them programmatically. This is fine, but instead of using addChild to append a child, you’ll need to place the new element in the DOM yourself using dojo.place(myDynamicElement.domNode, myExistingElement.domNode);.
• Specifying the top level widget
  If you use dojo’s markup method (with djConfig="parseOnLoad:true" set or running dojo.parser.parse()), the top level widgets are determined automatically. With this method, we need to manually start it by calling startup() on the top level widget (in our case, the mainContainer element). Otherwise, no layout occurs at all.

Interaction with checkboxes has changed slightly in Dojo 1.1 (apparently) but myCheckbox.setValue(true) should be valid. When calling dojo.byId('my-checkbox-id').setValue(true), I was getting an error saying the method didn’t exist. The object was definitely the checkbox as I could determine the correct checked state from that object (myCheckbox.checked) so I was very confused. I then remembered another way to access objects with Dojo is using the HTML attribute ‘jsId‘. This creates a global javascript variable referring to that object in the DOM. So I set something like jsId='myCheckbox' and then called myCheckbox.setValue(true) and it worked!

Very odd behaviour. I can only guess that the javascript object created by Dojo using jsId and dojo.byId() is a different bit of code and creates an object pointing to the DOM checkbox object in a different way. Very strange but at least there’s the workaround above…