jQuery 各类判断函数汇总

前端开发 作者: 2024-08-26 00:25:01
欢迎访问我的github:huanshen,有我的源码解析 常用的判断函数有type,isEmptyObject,isFunction,isWindow,isPlainObject,isArrayli
type: function( obj ) {
        if ( obj == null ) {
            return String( obj );
        }
        // Support: Safari <= 5.1 (functionish RegExp)
         利用事先存好的 hash 表 class2type 作精准判断
        return typeof obj === "object" || typeof obj === "function" ?
            class2type[ core_toString.call(obj) ] || "object" :
            typeof obj;
    },
 Populate the class2type map
jQuery.each("Boolean Number String Function Array Date RegExp Object Error".split(" "),(i,name) {
    class2type[ "[object " + name + "]" ] = name.toLowerCase();
});
var obj={ };arr=[];
    console.log(obj.toString.call(arr));[object Array]
    console.log(obj.toString.call(obj));[object Object]
3、数字isNumeric
4、函数isFunction
isFunction: return jQuery.type(obj) === "function"5、isWindow
 6、isArray
利用数组自带的isArray来判断
 7、isPlainObject

        if ( jQuery.type( obj ) !== "object" || obj.nodeType || jQuery.isWindow( obj ) ) {
            ;
        }

         Support: Firefox <20
         The try/catch suppresses exceptions thrown when attempting to access
         the "constructor" property of certain host objects,ie. |window.location|
         https://bugzilla.mozilla.org/show_bug.cgi?id=814622
        try {
            if ( obj.constructor &&
                    !core_hasOwn.call( obj.constructor.prototype,"isPrototypeOf" ) ) {
                ;
            }
        } catch ( e ) {
             If the function hasn't returned already,we're confident that
         |obj| is a plain object,created by {} or constructed with new Object
        isArraylike

     (such as loading iframes in IE - #4833)
    var documentElement = elem && (elem.ownerDocument || elem).documentElement;
    xml的根节点不可能是HTML
    return documentElement ? documentElement.nodeName !== "HTML" : ;
};
 Support tests
    不是xml就是HTML
    documentIsHTML = !isXML( doc );
原创声明
本站部分文章基于互联网的整理,我们会把真正“有用/优质”的文章整理提供给各位开发者。本文来自互联网用户投稿,该文观点仅代表作者本人,不代表本站立场。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。
本文链接:http://www.jiecseo.com/news/show_68680.html