Imagine the possibilities ahead of you with the ability to enforce iteration anytime you please .
Notes : jQuery also provides a $. each function , not to be confused with the $(). each method , which is used specifically to iterate over a jQuery wrapper set . The $. each method can actually be used to iterate over any old JavaScript array or object . It is essentailly a substitue for native JavaScript loops .
Elements in jQuery wrapper set returned in document order
The selector engine will return results in document order as opposed to the order in which the selectors were passed in . The wrapper set will be populated with the selected elements based on the order each element appears in the document , from top to bottom .
Sample : sample19 . html
<! DOCTYPE html > < html lang =" en "> < body > < h1 > h1 </ h1 > < h2 > h2 </ h2 > < h3 > h3 </ h3 > < script src =" http :// ajax . googleapis . com / ajax / libs / jquery / 1.7.2 / jquery . min . js "></ script >
< script > ( function ($) { // We pass in h3 first , but h1 appears earlier in // the document , so it is first in the wrapper set . alert ($(' h3 , h2 , h1 '). get ( 0 ). nodeName ); // Alerts " H1 ".
})( jQuery );
</ script > </ body > </ html >
Determining context used by the jQuery function
The default context used by the jQuery function when selecting DOM elements is the document element ( e . g . $(' a ', document )). This means that if you do not provide the jQuery function ( e . g . jQuery ()) with a second parameter to be used as the context for the DOM query , the default context used is the document element , more commonly known as < body >.
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