YUI read code Diary of Yahoo.util.dom-part.1_yui. Ext Related

Get around the head a lot of if...else (in fact, define Tocamel and GetStyle two functions)-because the browser's implementation is not uniform, causing such a cumbersome situation, you can talk about the code back.

Below we look at the treasures in the YAHOO.util.Dom class. Now that the thought has gradually split, I see a function that says a function.

It's basically a document.getElementById version.
Get:function (EL) {
If it's already htmlelement, then go straight back.
if (El && (El.nodetype | | el.item)) {
Return el;
}

If it is a string, then the Element with this ID is returned
if (YAHOO.lang.isString (EL) | |!el) {
Return document.getElementById (EL);
}

Looks like a number of groups, loops call itself, gets eelement
if (el.length!== undefined) {
var c = [];
for (var i = 0, len = el.length i < len; ++i) {
C[c.length] = Y.dom.get (El[i]);
}

return C;
}

Return el;
This code is very subtle. Frankly, the loop body in the above code, if not without thinking, would be written

for (var i = 0, len = el.length i < len; ++i) {
C[c.length] = document.getElementById (El[i]);
Although it works, the previous judgment loses its meaning.

Go on, and now look at the internal mechanism of getelementsbyclassname. Detailed call on Getelementsbyclassname, you can see the YUI document.

Getelementsbyclassname:function (ClassName, tag, root, apply) {
Get Tag label, default to All ("*")
Tag = Tag | | '*';
Designation of the following section
root = (root)? Y.dom.get (root): null | | Document
if (!root) {
return [];
}

Initializing node information
var nodes = [],
elements = root.getelementsbytagname (tag),
Re = Getclassregex (className);

Filter out nodes that don't conform to the rules
for (var i = 0, len = elements.length i < len; ++i) {
if (Re.test (Elements[i].classname)) {
You must be wondering why you use nodes.length instead of I
Careful consideration of: ^)
Nodes[nodes.length] = elements[i];
Executing a callback function
if (apply) {
Apply.call (Elements[i], elements[i]);
}
}
}

return nodes;
, the Textbook DOM node acquisition and filtering, initialization data and operational data are very rigorous and formal, YUI code let me have a bit of "security." Similarly, another Getelementsby function, the corresponding code is as follows

Getelementsby:function (method, tag, root, apply) {
The same as the above function, slightly
Tag = Tag | | '*';
root = (root)? Y.dom.get (root): null | | Document

if (!root) {
return [];
}

var nodes = [],
elements = root.getelementsbytagname (tag);

for (var i = 0, len = elements.length i < len; ++i) {
Determining the properties of a node based on the return value of a custom function
if (method (Elements[i])) {
Nodes[nodes.length] = elements[i];
if (apply) {
Apply (Elements[i]);
}
}
}

return nodes;
},ok, let's get here today.