source: Dev/trunk/src/client/dojo/dom.js @ 501

define(["./sniff", "./_base/window"],
                function(has, win){
        // module:
        //              dojo/dom

        // FIXME: need to add unit tests for all the semi-public methods

        if(has("ie") <= 7){
                try{
                        document.execCommand("BackgroundImageCache", false, true);
                }catch(e){
                        // sane browsers don't have cache "issues"
                }
        }

        // =============================
        // DOM Functions
        // =============================

        // the result object
        var dom = {
                // summary:
                //              This module defines the core dojo DOM API.
        };

        if(has("ie")){
                dom.byId = function(id, doc){
                        if(typeof id != "string"){
                                return id;
                        }
                        var _d = doc || win.doc, te = id && _d.getElementById(id);
                        // attributes.id.value is better than just id in case the
                        // user has a name=id inside a form
                        if(te && (te.attributes.id.value == id || te.id == id)){
                                return te;
                        }else{
                                var eles = _d.all[id];
                                if(!eles || eles.nodeName){
                                        eles = [eles];
                                }
                                // if more than 1, choose first with the correct id
                                var i = 0;
                                while((te = eles[i++])){
                                        if((te.attributes && te.attributes.id && te.attributes.id.value == id) || te.id == id){
                                                return te;
                                        }
                                }
                        }
                };
        }else{
                dom.byId = function(id, doc){
                        // inline'd type check.
                        // be sure to return null per documentation, to match IE branch.
                        return ((typeof id == "string") ? (doc || win.doc).getElementById(id) : id) || null; // DOMNode
                };
        }
        /*=====
         dom.byId = function(id, doc){
                // summary:
                //              Returns DOM node with matching `id` attribute or falsy value (ex: null or undefined)
                //              if not found.  If `id` is a DomNode, this function is a no-op.
                //
                // id: String|DOMNode
                //              A string to match an HTML id attribute or a reference to a DOM Node
                //
                // doc: Document?
                //              Document to work in. Defaults to the current value of
                //              dojo/_base/window.doc.  Can be used to retrieve
                //              node references from other documents.
                //
                // example:
                //              Look up a node by ID:
                //      |       require(["dojo/dom"], function(dom){
                //      |               var n = dom.byId("foo");
                //      |       });
                //
                // example:
                //              Check if a node exists, and use it.
                //      |       require(["dojo/dom"], function(dom){
                //      |               var n = dom.byId("bar");
                //      |               if(n){ doStuff() ... }
                //      |       });
                //
                // example:
                //              Allow string or DomNode references to be passed to a custom function:
                //      |       require(["dojo/dom"], function(dom){
                //      |               var foo = function(nodeOrId){
                //      |                       nodeOrId = dom.byId(nodeOrId);
                //      |                       // ... more stuff
                //      |               }
                //      |       });
         };
         =====*/

        dom.isDescendant = function(/*DOMNode|String*/ node, /*DOMNode|String*/ ancestor){
                // summary:
                //              Returns true if node is a descendant of ancestor
                // node: DOMNode|String
                //              string id or node reference to test
                // ancestor: DOMNode|String
                //              string id or node reference of potential parent to test against
                //
                // example:
                //              Test is node id="bar" is a descendant of node id="foo"
                //      |       require(["dojo/dom"], function(dom){
                //      |               if(dom.isDescendant("bar", "foo")){ ... }
                //      |       });

                try{
                        node = dom.byId(node);
                        ancestor = dom.byId(ancestor);
                        while(node){
                                if(node == ancestor){
                                        return true; // Boolean
                                }
                                node = node.parentNode;
                        }
                }catch(e){ /* squelch, return false */ }
                return false; // Boolean
        };


        // TODO: do we need setSelectable in the base?

        // Add feature test for user-select CSS property
        // (currently known to work in all but IE < 10 and Opera)
        has.add("css-user-select", function(global, doc, element){
                // Avoid exception when dom.js is loaded in non-browser environments
                if(!element){ return false; }
                
                var style = element.style;
                var prefixes = ["Khtml", "O", "ms", "Moz", "Webkit"],
                        i = prefixes.length,
                        name = "userSelect",
                        prefix;

                // Iterate prefixes from most to least likely
                do{
                        if(typeof style[name] !== "undefined"){
                                // Supported; return property name
                                return name;
                        }
                }while(i-- && (name = prefixes[i] + "UserSelect"));

                // Not supported if we didn't return before now
                return false;
        });

        /*=====
        dom.setSelectable = function(node, selectable){
                // summary:
                //              Enable or disable selection on a node
                // node: DOMNode|String
                //              id or reference to node
                // selectable: Boolean
                //              state to put the node in. false indicates unselectable, true
                //              allows selection.
                // example:
                //              Make the node id="bar" unselectable
                //      |       require(["dojo/dom"], function(dom){
                //      |               dom.setSelectable("bar");
                //      |       });
                // example:
                //              Make the node id="bar" selectable
                //      |       require(["dojo/dom"], function(dom){
                //      |               dom.setSelectable("bar", true);
                //      |       });
        };
        =====*/

        var cssUserSelect = has("css-user-select");
        dom.setSelectable = cssUserSelect ? function(node, selectable){
                // css-user-select returns a (possibly vendor-prefixed) CSS property name
                dom.byId(node).style[cssUserSelect] = selectable ? "" : "none";
        } : function(node, selectable){
                node = dom.byId(node);

                // (IE < 10 / Opera) Fall back to setting/removing the
                // unselectable attribute on the element and all its children
                var nodes = node.getElementsByTagName("*"),
                        i = nodes.length;

                if(selectable){
                        node.removeAttribute("unselectable");
                        while(i--){
                                nodes[i].removeAttribute("unselectable");
                        }
                }else{
                        node.setAttribute("unselectable", "on");
                        while(i--){
                                nodes[i].setAttribute("unselectable", "on");
                        }
                }
        };

        return dom;
});