jQuery:检查是否将元素分配给变量 [英] jQuery: Check if an element is assigned to a var

问题描述

我正在尝试创建一个简单的按钮管理器，以选择并最终取消选择所有已检查的包含CSS类.my_class的img元素，为什么它不起作用?

I'm trying to create a simple button manager to select and eventually unselect allready checked img elements which contains CSS class .my_class, why this doesn't work?

var last_selected;
$("img.my_class").click ( function () {
    if (last_selected != null) alert ($(this) == last_selected); // returns false everytime
    last_selected =  $(this);
});

推荐答案

每次包装this时，都会创建一个新的jQuery对象.两个jQuery对象彼此不相等，只是因为它们包装了相同的元素($(this) != $(this)).

Each time you wrap this you create a new jQuery object. Two jQuery objects are not equal to each other just because they wrap the same element ($(this) != $(this)).

相反，将this本身分配给last_selected，一切都应按预期工作.

Instead, assign this itself to last_selected and everything should work as expected.

var last_selected;
$("img.my_class").click ( function () {
    if (last_selected != null) alert (this == last_selected);
    last_selected = this;
});

这篇关于jQuery:检查是否将元素分配给变量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！