# Class Ext.DomQuery

Package: | Ext
Defined In: | DomQuery.js
Class: | DomQuery
Extends: | Object

Provides high performance selector/xpath processing by compiling queries into reusable functions. New pseudo classes and matchers can be plugged. It works on HTML and XML documents (if a content node is passed in).

DomQuery supports most of the CSS3 selectors spec, along with some custom selectors and basic XPath.

All selectors, attribute filters and pseudos below can be combined infinitely in any order. For example "div.foo:nth-child(odd)[@foo=bar].bar:first" would be a perfectly valid selector. Node filters are processed in the order in which they appear, which allows you to optimize your queries for your document structure.

#### Element Selectors:

- * any element
- E an element with the tag E
- E F All descendent elements of E that have the tag F
- E > F or E/F all direct children elements of E that have the tag F
- E + F all elements with the tag F that are immediately preceded by an element with the tag E
- E ~ F all elements with the tag F that are preceded by a sibling element with the tag E

#### Attribute Selectors:

The use of @ and quotes are optional. For example, div[@foo='bar'] is also a valid attribute selector.

- E[foo] has an attribute "foo"
- E[foo=bar] has an attribute "foo" that equals "bar"
- E[foo^=bar] has an attribute "foo" that starts with "bar"
- E[foo$=bar] has an attribute "foo" that ends with "bar"
- E[foo*=bar] has an attribute "foo" that contains the substring "bar"
- E[foo%=2] has an attribute "foo" that is evenly divisible by 2
- E[foo!=bar] attribute "foo" does not equal "bar"

#### Pseudo Classes:

- E:first-child E is the first child of its parent
- E:last-child E is the last child of its parent
- E:nth-child(n) E is the nth child of its parent (1 based as per the spec)
- E:nth-child(odd) E is an odd child of its parent
- E:nth-child(even) E is an even child of its parent
- E:only-child E is the only child of its parent
- E:checked E is an element that is has a checked attribute that is true (e.g. a radio or checkbox)
- E:first the first E in the resultset
- E:last the last E in the resultset
- E:nth(n) the nth E in the resultset (1 based)
- E:odd shortcut for :nth-child(odd)
- E:even shortcut for :nth-child(even)
- E:contains(foo) E's innerHTML contains the substring "foo"
- E:nodeValue(foo) E contains a textNode with a nodeValue that equals "foo"
- E:not(S) an E element that does not match simple selector S
- E:has(S) an E element that has a descendent that matches simple selector S
- E:next(S) an E element whose next sibling matches simple selector S
- E:prev(S) an E element whose previous sibling matches simple selector S
- E:any(S1|S2|S2) an E element which matches any of the simple selectors S1, S2 or S3//\\

#### CSS Value Selectors:

- E{display=none} css value "display" that equals "none"
- E{display^=none} css value "display" that starts with "none"
- E{display$=none} css value "display" that ends with "none"
- E{display*=none} css value "display" that contains the substring "none"
- E{display%=2} css value "display" that is evenly divisible by 2
- E{display!=none} css value "display" that does not equal "none"

This class is a singleton and cannot be created directly.

## Public Properties

Property | Defined By
--- | ---
| matchers : Object Collection of matching regular expressions and code snippets. Each capture group within () will be replace the {} in ... Collection of matching regular expressions and code snippets. Each capture group within () will be replace the {} in the select statement as specified by their index. | DomQuery
| pseudos : Object Object hash of "pseudo class" filter functions which are used when filtering selections. Each function is passed two ... Object hash of "pseudo class" filter functions which are used when filtering selections. Each function is passed two parameters: c : Array An Array of DOM elements to filter. v : String The argument (if any) supplied in the selector. A filter function returns an Array of DOM elements which conform to the pseudo class. In addition to the provided pseudo classes listed above such as `first-child` and `nth-child`, developers may add additional, custom psuedo class filters to select elements according to application-specific requirements. For example, to filter `<a>` elements to only return links to external resources: `
    Ext.DomQuery.pseudos.external = function(c, v){
        var r = [], ri = -1;
        for(var i = 0, ci; ci = c[i]; i++){
    //      Include in result set only if it's a link to an external resource
            if(ci.hostname != location.hostname){
                r[++ri] = ci;
            }
        }
        return r;
    };
` Then external links could be gathered with the following statement:`
    var externalLinks = Ext.select("a:external");
` | DomQuery

## Public Methods

Method | Defined By
--- | ---
| compile( String selector, [String type] ) : Function Compiles a selector/xpath query into a reusable function. The returned function takes one parameter "root" (optional)... Compiles a selector/xpath query into a reusable function. The returned function takes one parameter "root" (optional), which is the context node from where the query should start. Parameters: `selector` : String The selector/xpath query `type` : String (optional) Either "select" (the default) or "simple" for a simple selector match Returns: `Function` | DomQuery
| filter( Array el, String selector, Boolean nonMatches ) : Array Filters an array of elements to only include matches of a simple selector (e.g. div.some-class or span:first-child) Filters an array of elements to only include matches of a simple selector (e.g. div.some-class or span:first-child) Parameters: `el` : Array An array of elements to filter `selector` : String The simple selector to test `nonMatches` : Boolean If true, it returns the elements that DON'T match the selector instead of the ones that match Returns: `Array` An Array of DOM elements which match the selector. If there are no matches, and empty Array is returned. | DomQuery
| is( String/HTMLElement/Array el, String selector ) : Boolean Returns true if the passed element(s) match the passed simple selector (e.g. div.some-class or span:first-child) Returns true if the passed element(s) match the passed simple selector (e.g. div.some-class or span:first-child) Parameters: `el` : String/HTMLElement/Array An element id, element or array of elements `selector` : String The simple selector to test Returns: `Boolean` | DomQuery
| jsSelect( String selector, [Node/String root] ) : Array Selects a group of elements. Selects a group of elements. Parameters: `selector` : String The selector/xpath query (can be a comma separated list of selectors) `root` : Node/String (optional) The start of the query (defaults to document). Returns: `Array` An Array of DOM elements which match the selector. If there are no matches, and empty Array is returned. | DomQuery
| operators() : void Collection of operator comparison functions. The default operators are =, !=, ^=, $=, *=, %=, |= and ~=. New operator... Collection of operator comparison functions. The default operators are =, !=, ^=, $=, *=, %=, |= and ~=. New operators can be added as long as the match the format c= where c is any character other than space, > <. Parameters: None. Returns: void | DomQuery
| selectNode( String selector, [Node root] ) : Element Selects a single element. Selects a single element. Parameters: `selector` : String The selector/xpath query `root` : Node (optional) The start of the query (defaults to document). Returns: `Element` The DOM element which matched the selector. | DomQuery
| selectNumber( String selector, [Node root], Number defaultValue ) : Number Selects the value of a node, parsing integers and floats. Returns the defaultValue, or 0 if none is specified. Selects the value of a node, parsing integers and floats. Returns the defaultValue, or 0 if none is specified. Parameters: `selector` : String The selector/xpath query `root` : Node (optional) The start of the query (defaults to document). `defaultValue` : Number Returns: `Number` | DomQuery
| selectValue( String selector, [Node root], String defaultValue ) : String Selects the value of a node, optionally replacing null with the defaultValue. Selects the value of a node, optionally replacing null with the defaultValue. Parameters: `selector` : String The selector/xpath query `root` : Node (optional) The start of the query (defaults to document). `defaultValue` : String Returns: `String` | DomQuery

## Public Events

This class has no public events.