jQuery Cookbook - Cdn.oreilly.com - O'Reilly

More documents

Recommendations

Info

"4 inputs" alert('selected' + jQuery('input',document.forms[0]).length + ' inputs'); //search within the body element for all input elements using an expression, //alerts "12 inputs" alert('selected' + jQuery('input','body').length + ' inputs'); Discussion It’s also possible, as mentioned in the solution of this recipe, to select documents as the context for searching. For example, it’s possible to search within the context of an XML document that is sent back from doing an XHR request (Ajax). You can find more details about this usage in Chapter 16. 1.5 Filtering a Wrapper Set of DOM Elements Problem You have a set of selected DOM elements in a jQuery wrapper set but want to remove DOM elements from the set that do not match a new specified expression(s) in order to create a new set of elements to operate on. Solution The jQuery filter method, used on a jQuery wrapper set of DOM elements, can exclude elements that do not match a specified expression(s). In short, the filter() method allows you to filter the current set of elements. This is an important distinction from the jQuery find method, which will reduce a wrapped set of DOM elements by finding (via a new selector expression) new elements, including child elements of the current wrapped set. To understand the filter method, let’s examine the following code: link link link link 16 | Chapter 1: jQuery Basics
link link link link //alerts 4 left in the set alert(jQuery('a').filter('.external').length + ' external links'); The HTML page in the code example just shown contains a web page with 10 elements. Those links that are external links are given a class name of external. Using the jQuery function, we select all elements on the page. Then, using the filter method, all those elements that do not have a class attribute value of external are removed from the original set. Once the initial set of DOM elements are altered using the filter() method, I invoke the length property, which will tell me how many elements are now in my new set after the filter has been applied. Discussion It’s also possible to send the filter() method a function that can be used to filter the wrapped set. Our previous code example, which passes the filter() method a string expression, can be changed to use a function instead: alert( jQuery('a') .filter(function(index){ return $(this).hasClass('external');}) .length + ' external links' ); Notice that I am now passing the filter() method an anonymous function. This function is called with a context equal to the current element. That means when I use $(this) within the function, I am actually referring to each DOM element in the wrapper set. Within the function, I am checking each element in the wrapper set to see whether the element has a class value (hasClass()) of external. If it does, Boolean true, then keep the element in the set, and if it doesn’t (false), then remove the element from the set. Another way to look at this is if the function returns false, then the element is removed. If the function returns any other data value besides false, then the element will remain in the wrapper set. You may have noticed that I have passed the function a parameter named index that I am not using. This parameter, if needed, can be used to refer numerically to the index of the element in the jQuery wrapper set. 1.5 Filtering a Wrapper Set of DOM Elements | 17
Page 1 and 2: Solutions & Examples for jQuery Dev
Page 3: jQuery Cookbook
Page 6 and 7: jQuery Cookbook by jQuery Community
Page 8 and 9: 2.3 Selecting Elements by Index Ord
Page 10 and 11: 8.5 Passing Dynamic Data to Event H
Page 12 and 13: 16.5 Using HTML Fragments and jQuer
Page 14 and 15: This is largely what makes somethin
Page 16 and 17: on client-side optimization techniq
Page 18 and 19: Tech Editors Karl Swedberg, after h
Page 20 and 21: What You’ll Learn We’ll start o
Page 22 and 23: If none of this works, it’s possi
Page 24 and 25: 800-998-9938 (in the United States
Page 26 and 27: traversing and manipulation, browse
Page 28 and 29: • Using the jQuery wrapper and im
Page 30 and 31: The jQuery wrapper set A good major
Page 32 and 33: — Attr — Class — HTML — Tex
Page 34 and 35: alert('jQuery ' + jQuery.fn.jquery)
Page 36 and 37: alert(jQuery('p').text()); }); T
Page 38 and 39: You should be aware that the first
Page 42 and 43: 1.6 Finding Descendant Elements Wit
Page 44 and 45: .end().end().length); //alerts 3
Page 46 and 47: Now, let’s select the second ele
Page 48 and 49: jQuery('jQuery').find('a').attr('hr
Page 50 and 51: • While the elements selected are
Page 52 and 53: Discussion The cloning method is ac
Page 54 and 55: method by passing the method the at
Page 56 and 57: jQuery('p').text('Hello World,
Page 59 and 60: 2.0 Introduction CHAPTER 2 Selectin
Page 61 and 62: It’s worth noting that combinator
Page 63 and 64: all siblings that follow, not just
Page 65 and 66: Discussion As mentioned, an element
Page 67 and 68: 2.6 Selecting Elements by What They
Page 69 and 70: The preceding selector would select
Page 71 and 72: These filters can also be used with
Page 73 and 74: Solution As well as passing a selec
Page 75: The purpose of the selector would b
Page 78 and 79: alert(urls.join(",")); We were able
Page 80 and 81: Even though this may be the most ob
Page 82 and 83: Figure 3-2. Code output As you can
Page 84 and 85: Chapter 3 - Recipe 3 - Converting a
Page 86 and 87: Figure 3-4. Code output 3.4 Getting
Page 88 and 89: Discussion The core method index()
Page 90 and 91:
Figure 3-6. Code output In the prec
Page 92 and 93:
ligula. Aenean mattis pulvinar est
Page 94 and 95:
Solution Let’s say you inherit a
Page 96 and 97:
If you use this technique, you will
Page 98 and 99:
available on the Web. jQuery hosts
Page 100 and 101:
Discussion In the preceding example
Page 102 and 103:
.click(function() { // Special clic
Page 104 and 105:
}); })(jQuery); 4.3 Filtering Array
Page 106 and 107:
Discussion In this example, we have
Page 108 and 109:
}); }); })(jQuery); Discussion Upon
Page 110 and 111:
Discussion In this recipe, we use t
Page 112 and 113:
Solution The if/else statement and
Page 114 and 115:
var foo = new Foo( 'bar' ); foo.ale
Page 116 and 117:
} $('#province').toggle( value == '
Page 118 and 119:
Did jQuery invent chaining? No. jQu
Page 120 and 121:
Whether the idea comes from elsewhe
Page 122 and 123:
}; return object; That could also b
Page 124 and 125:
null or undefined, remove the attri
Page 126 and 127:
The +new Date in this code is just
Page 128 and 129:
(function() { var log = [], index =
Page 130 and 131:
The page also contains a large numb
Page 132 and 133:
you could use this: $('.clientX') /
Page 134 and 135:
And you have this HTML code in your
Page 136 and 137:
when you discover the slow parts, y
Page 138 and 139:
A Warning About for..in Loops Never
Page 140 and 141:
Other code here calls maxMagnitude
Page 142 and 143:
matter, but in performance-critical
Page 144 and 145:
console.log( $foo ); $foo.css({ fon
Page 146 and 147:
Solution 1 You’re using the minif
Page 148 and 149:
After the page loads, you are down
Page 150 and 151:
5.19 Writing Unobtrusive JavaScript
Page 152 and 153:
Documentation Tutorials We’ve
Page 154 and 155:
Beware that you don’t make the us
Page 156 and 157:
+ $(document).scrollLeft() }) .show
Page 158:
Want to read more? You can find thi
show all

jQuery Cookbook - Cdn.oreilly.com - O'Reilly

Create successful ePaper yourself

Delete template?

Save as template?