Chapter 7. Utility Functions
The jQuery library defines a number of utility functions (as well as two properties) that you may find useful in your programs. As you’ll see in the list below, a number of these functions now have equivalents in ECMAScript 5 (ES5). jQuery’s functions predate ES5 and work in all browsers. In alphabetical order, the utility functions are:
jQuery.browser
The
browser
property is not a function, but an object that you can use for client sniffing or browser testing. This object will have the propertymsie
set totrue
if the browser is IE. Themozilla
property will be true if the browser is Firefox or related. Thewebkit
property will be true for Safari and Chrome, and theopera
property will be true for Opera. In addition to this browser-specific property, theversion
property contains the browser version number. Client sniffing is best avoided whenever possible, but you can use this property to work around browser-specific bugs with code like this:if ($.browser.mozilla && parseInt($.browser.version) < 4) { // Work around a hypothetical Firefox bug here. }
jQuery.contains()
This function expects two document elements as its arguments. It returns
true
if the first element contains the second element, and returnsfalse
otherwise.jQuery.each()
Unlike the
each()
method, which iterates only over jQuery objects, thejQuery.each()
utility function iterates through the elements of an array or the properties of an object. The first argument is the array or object to be ...
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