sizzle

For some reason, I am getting the following Javascript error in Internet Explorer 8 on line 3156 of jquery.js (version 1.4.3, non-compressed version): Object doesn't support this property or method . No error occurs in Firefox and Google Chrome. This is the line the error occurs on: if ( (match = Expr.leftMatch[ type ].exec( expr )) != null && match[2] ) { Investigation ( console.log(Expr.leftMatch[type]) ) produces the following interesting result: In Google Chrome, it outputs /(^(?:.|\r|\n)*?):((?:[\w\u00c0-\uFFFF\-]|\\.)+)(?:\((['"]?)((?:\([^\)]+\)|[^\(\)]*)+)\3\))?(?![^\[]*\])(?![^\(]*\))/

Say I make a mistake when I'm trying to find an element and I make a typo, like $('lsdkfj') . Instead of jQuery returning me an empty array, I'd like to return an error message in the console, like "The selector 'lsdkfj' cannot be found" . What is the best way to go about doing this? Like this: var oldInit = $.fn.init; $.fn.init = function(selector, context, rootjQuery) { var result = new oldInit(selector, context, rootjQuery); if (result.length === 0) console.info("jQuery call has no elements!", arguments); return result; }; 来源： https://stackoverflow.com/questions/5744997/how-do-i-extend

I have this: <ul> <li>first</li> <li>second</li> <li>third</li> <li>fourth</li> </ul> Then I select it all with jQuery: $('ul').find('li'); or $('ul li'); How can I, from those two jQuery selectors get the, for instance only second li, or third, and to leave first and fourt alone? I thought it might work with: $('myselector').get(indexNumber); // however, it won't work. Any ideas for this issue? Thanks. The get method returns the DOM element, so then you would have to wrap it inside a new jQuery object. You can use the eq method: var j = $('ul li').eq(1); // gets the second list item Use :eq()

When used with the child selector > , the two variants of jQuery's "has" behave differently. Take this HTML: <div> <span>Text</span> </div> Now: $("div:has(>span)"); would return it, while: $("div").has(">span"); would not. Is it a bug or a feature? Compare here: http://jsfiddle.net/aC9dP/ EDIT: This may be a bug or at least undocumented inconsistent behavior. Anyway, I think it would be beneficial to have the child selector consistently work as an unary operator. It enables you to do something that otherwise would require a custom filter function — it lets you directly select elements that

While working on a script recently, I came across a peculiar nuance of how Sizzle works with the href attribute . Specifically, using an attribute selector on an href , Sizzle will use the actual attribute value: // Will not find <a href="index.html">... $('a[href="http://www.example.com/index.html"]') Sizzle uses .getAttribute() instead of elem.href (or more precisely, elem['href'] , as Sizzle does in most cases ); elem.href would provide the fully-qualified URL. To understand this a bit more, I created a fiddle to try different forms of URLs . In the process of testing, I discovered the

As a example of jQuery code ( https://coderwall.com/p/7uchvg ), I read that the expression $('#foo a'); behaves like this: Find every a in the page and then filter a inside #foo . And it does not look efficient. Is that correct? And if yes, how should we do that in a better way? That is correct - Sizzle (jQuery's selector engine) behaves the same way as CSS selectors . CSS and Sizzle selectors are evaluated right-to-left , and so #foo a will find all a nodes, then filter those by nodes that descend from #foo . You improve this by ensuring that your leaf selectors have a high specificity,

Is it possible to find all DOM elements with jQuery with wildcards in the attribute name? Consider the following HTML: <input id="val1" type="text" data-validate-required data-validate-minlength="3" data-validate-email /> What I am trying to achieve is to find all dom nodes with an attribute name starting with data-validate- As far as I understand the wildcards described here are concerned with "value" of the attribute. The reason for this is - I want to find out which elements should be validated at all - and afterwards find out which validation parameters (like -email) comes in play. Thanks