我知道$('.some-class')
和$('#some-id')
的含义,但我真的不知道$('.some-class',$('#some-id'))
的含义,希望有人可以为我解释,非常感谢。
答案 0 :(得分:4)
您selector
context
,some-class
将在元素中使用ID为some-id
的元素进行查找。
'.some-class'
是选择器,$('#some-id')
是上下文
选择器的jQuery文档中的语法是jQuery( selector [ , context ] )
,您可以阅读有关选择器的更多信息here
Without context
$('。some-class')将带有类some-class的文档中的所有元素。 With context
$('。some-class',$('#some-id'))将带有ID为some-id
的元素中的所有元素。
答案 1 :(得分:3)
第二个参数是上下文。
如果查看jQuery源代码,可以将其视为$或jQuery函数的第二个参数。
$('selector')遍历整个文档
$('selector',context)在给定的上下文/元素中遍历
来自jQuery库源的几行
(function( window, undefined ) {
// Define a local copy of jQuery
var jQuery = function( selector, context ) {
/// <summary>
/// 1: $(expression, context) - This function accepts a string containing a CSS selector which is then used to match a set of elements.
/// 2: $(html) - Create DOM elements on-the-fly from the provided String of raw HTML.
/// 3: $(elements) - Wrap jQuery functionality around a single or multiple DOM Element(s).
/// 4: $(callback) - A shorthand for $(document).ready().
/// 5: $() - As of jQuery 1.4, if you pass no arguments in to the jQuery() method, an empty jQuery set will be returned.
/// </summary>
/// <param name="selector" type="String">
/// 1: expression - An expression to search with.
/// 2: html - A string of HTML to create on the fly.
/// 3: elements - DOM element(s) to be encapsulated by a jQuery object.
/// 4: callback - The function to execute when the DOM is ready.
/// </param>
/// <param name="context" type="jQuery">
/// 1: context - A DOM Element, Document or jQuery to use as context.
/// </param>
/// <returns type="jQuery" />
// The jQuery object is actually just the init constructor 'enhanced'
return new jQuery.fn.init( selector, context );
},
答案 2 :(得分:1)
您在.some-class
中搜索#some-id
。