The DomHelper class provides a layer of abstraction from DOM and transparently supports creating
+ * elements via DOM or using HTML fragments. It also has the ability to create HTML fragment templates
+ * from your DOM building code.
+ *
+ *
DomHelper element specification object
+ *
A specification object is used when creating elements. Attributes of this object
+ * are assumed to be element attributes, except for 4 special attributes:
+ *
+ *
tag :
The tag name of the element
+ *
children : or cn
An array of the
+ * same kind of element definition objects to be created and appended. These can be nested
+ * as deep as you want.
+ *
cls :
The class attribute of the element.
+ * This will end up being either the "class" attribute on a HTML fragment or className
+ * for a DOM node, depending on whether DomHelper is using fragments or DOM.
+ *
html :
The innerHTML for the element
+ *
+ *
+ *
Insertion methods
+ *
Commonly used insertion methods:
+ *
+ *
{@link #append} :
+ *
{@link #insertBefore} :
+ *
{@link #insertAfter} :
+ *
{@link #overwrite} :
+ *
{@link #createTemplate} :
+ *
{@link #insertHtml} :
+ *
+ *
+ *
Example
+ *
This is an example, where an unordered list with 3 children items is appended to an existing
+ * element with id 'my-div':
+
+var dh = Ext.DomHelper; // create shorthand alias
+// specification object
+var spec = {
+ id: 'my-ul',
+ tag: 'ul',
+ cls: 'my-list',
+ // append children after creating
+ children: [ // may also specify 'cn' instead of 'children'
+ {tag: 'li', id: 'item0', html: 'List Item 0'},
+ {tag: 'li', id: 'item1', html: 'List Item 1'},
+ {tag: 'li', id: 'item2', html: 'List Item 2'}
+ ]
+};
+var list = dh.append(
+ 'my-div', // the context element 'my-div' can either be the id or the actual node
+ spec // the specification object
+);
+
+ *
Element creation specification parameters in this class may also be passed as an Array of
+ * specification objects. This can be used to insert multiple sibling nodes into an existing
+ * container very efficiently. For example, to add more list items to the example above:
The real power is in the built-in templating. Instead of creating or appending any elements,
+ * {@link #createTemplate} returns a Template object which can be used over and over to
+ * insert new elements. Revisiting the example above, we could utilize templating this time:
+ *
+// create the node
+var list = dh.append('my-div', {tag: 'ul', cls: 'my-list'});
+// get template
+var tpl = dh.createTemplate({tag: 'li', id: 'item{0}', html: 'List Item {0}'});
+
+for(var i = 0; i < 5, i++){
+ tpl.append(list, [i]); // use template to append to the actual node
+}
+ *
Templates are applied using regular expressions. The performance is great, but if
+ * you are adding a bunch of DOM elements using the same template, you can increase
+ * performance even further by {@link Ext.Template#compile "compiling"} the template.
+ * The way "{@link Ext.Template#compile compile()}" works is the template is parsed and
+ * broken up at the different variable points and a dynamic function is created and eval'ed.
+ * The generated function performs string concatenation of these parts and the passed
+ * variables instead of using regular expressions.
+ *
+var html = '{text}';
+
+var tpl = new Ext.DomHelper.createTemplate(html);
+tpl.compile();
+
+//... use template like normal
+ *
+ *
+ *
Performance Boost
+ *
DomHelper will transparently create HTML fragments when it can. Using HTML fragments instead
+ * of DOM can significantly boost performance.
+ *
Element creation specification parameters may also be strings. If {@link #useDom} is false,
+ * then the string is used as innerHTML. If {@link #useDom} is true, a string specification
+ * results in the creation of a text node. Usage:
+ *
+Ext.DomHelper.useDom = true; // force it to use DOM; reduces performance
+ *