JavaScript 中 array.size() 和 array.length 的区别

array.size() 方法在功能上等同于array.length 属性，它只能在jQuery中使用。在 JavaScript 中array.size()是无效的方法，所以应该使用array.length 属性。下面的例子实现了上述概念：

示例 1：此示例演示了 array.size() 方法和 array.length 属性。

html

 

    
        Difference between array.size() method
        and array.length property
    

 

     

        Click the button to display
        the length of array.
    
 
 
    
        Try it
    
 
     

        Length of the array is:
        
    
 
 
    
        var arr = ['geeks', 'for', 'geeks'];
 
        function findLength() {
            document.getElementById("demo").innerHTML
                        = arr.length;
             
            document.getElementById("demo").innerHTML
                        = arr.size();
        }
    

 

输出：

Length of the array is: 3
error on console: TypeError: arr.size is not a function

注意：对于具有数字索引值的数组， array.length 属性返回 last_key+1 的值。此属性不保证找到数组中的项目数。

示例 2：此示例显示 Array.length 属性的工作原理。

html

 

    
        Array.length property
    

 

     

        Click the button to display
        the length of array.
    
 
 
    
        Try it
    
 
     

        Length of array the is:
        
    
 
 
    
        var arr = ['geeks', 'for', 'geeks'];
        arr[50] = 'article';
         
        function findLength() {
            document.getElementById("demo")
                        .innerHTML = arr.length;
        }
    

 

输出：

Length of the array is: 51

示例 3：此示例显示当索引键为非数字时 array.length 属性如何工作。

html

 

    
        array.length property with
        non-numeric index key
    

 

     

        Click the button to display
        the length of array.
    
 
 
    
        Try it
    
 
     

        Length of array the is:
        
    
 
 
    
        var arr = new Array();
        arr['a'] = 1;
        arr['b'] = 2;
        arr['c'] = 3;
         
        function findLength() {
            document.getElementById("demo")
                    .innerHTML = arr.length;
        }
    

 

输出：

Length of the array is: 0

让我们以表格形式查看差异 - ：

	array.size()	array.length()
1.	This property returns the size of the array	This property returns the size of the array
2.	Its syntax is -: array.size()	Its syntax is -: array.length
3.	It cannot be used in Javascript but only used in Jquery	It is used in Javascript, not in jQuery
4.	This is a feature of jQuery	array.length is an ECMAScript1 feature.
5	Its supported browsers are -: Chrome , Internet Explorer, Firefox, Safari, Opera Microsoft Edge	Its supported browsers are -: Chrome , Internet Explorer, Firefox, Safari, Opera, Microsoft Edge