Check if object is a jQuery object

Is there a fast way of checking if an object is a jQuery object or a native JavaScript object?

example:

var o = {};
var e = $('#element');

function doStuff(o) {
    if (o.selector) {
        console.log('object is jQuery');
    }
}

doStuff(o);
doStuff(e);

obviously, the code above works but it's not safe. You could potentially add a selector key to the o object and get the same result. Is there a better way of making sure that the object actually is a jQuery object?

Something in line with (typeof obj == 'jquery')

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You can use the instanceof operator:

obj instanceof jQuery

Explanation : the jQuery function (aka $ ) is implemented as a constructor function. Constructor functions are to be called with the new prefix.

When you call $(foo) , internally jQuery translates this to new jQuery(foo) 1. JavaScript proceeds to initialize this inside the constructor function to point to a new instance of jQuery , setting it's properties to those found on jQuery.prototype (aka jQuery.fn ). Thus, you get a new object where instanceof jQuery is true .

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1It's actually new jQuery.prototype.init(foo) : the constructor logic has been offloaded to another constructor function called init , but the concept is the same.

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您也可以按照此处所述使用.jquery属性：http://api.jquery.com/jquery-2/

var a = { what: "A regular JS object" },
b = $('body');

if ( a.jquery ) { // falsy, since it's undefined
    alert(' a is a jQuery object! ');    
}

if ( b.jquery ) { // truthy, since it's a string
    alert(' b is a jQuery object! ');
}

---

查看instanceof操作符。

var isJqueryObject = obj instanceof jQuery

链接地址: http://www.djcxy.com/p/2410.html

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