javascript當中concat，join,slice用法

1.3（concat，join,slice）
馬克- to-win：馬克 java社區(qū)：防盜版實名手機尾號： 73203。
<html>
<head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
    <Script>
        /* 馬克-to-win：qixy: Array is a dynamic array.
         - myArray = new Array(aLength)
        - myArray = new Array(anItem1, anItem2, anItem3, ...)
        */
        var arr = new Array(1);//arr.length is 1,但是里面的東西是undefined， 所以這樣寫[undefined]
/*雖然arr是個object， 但是里面的東西是undefined*/
        document.write("typeof arr is "+typeof(arr));
        var a = new Array(2, 6, 5, "a");
         document.write("arr.length is "+arr.length+"a.length is "+a.length);
        var b = new Array(12, 14);
        arr[0] = "java";
        arr[1] = "intel";
        arr[2] = "microsoft";
        /* Property/method value type: Array object
       JavaScript syntax: - myArray.concat(someValues, ...)
       The result of this method is a new array consisting of the original array, plus the concatenation.
       The values that are passed to the method are added to the end of the array.
       If arrays are passed, they are flattened and their individual elements added.
       The method returns an array consisting of the original Array plus the concatenated values.
       If Array1 contains "AAA", "BBB", "CCC" and Array2 contains "000", "111", "222", then the method
   call Array1.concat(Array2) will return an array with all the elements in a single collection. The
    original arrays will be untouched.
        */
        document.write("arr.toString() is " + arr.toString() + "<br>");
        //與無參join()方法等同
        var arrconcat=arr.concat(a, b);
        document.write("arr.concat(a,b) is " + arrconcat + "<br>");
        /*Array.join() (Method)
        Concatenate array elements to make a string.
        Property/method value type: String primitive
        JavaScript syntax: - myArray.join(aSeparator)
        Argument list: aSeparator A string to place between array elements as the array is concatenated to form a string.
        //無參join()方法默認是用逗號連接
        */
        document.write("arr.join() is " + arr.join() + "<br>");
        //無參join()方法默認是用逗號連接
        document.write("arr.join(' & ') is " + arr.join(' & ') + "<br>");
        /* Array.reverse() (Method)
        Reverse the order of array elements.
        Property/method value type: Array object
        */
        document.write("arr.reverse() is " + arr.reverse() + "<br>");
        /*Array.sort() (Method)
        Sort the elements in an array.
        Property/method value type: Array object
        JavaScript syntax: - myArray.sort()
        */
        document.write("arr.sort() is " + arr.sort() + "<br>");
        //如果調用該方法時沒有參數(shù)，將按字母順序進行排序
        document.write("a is " + a + "<br>");
        /* returned  value type: Array object
     JavaScript syntax: - myArray.slice(aRange)
     a bit like substring, but substring is applicable to String, but slice is applicable to array.
     allegedly,it includes former,exclude latter，一薄片面包:a slice of bread*/
        var slicedArr = a.slice(0, 2);
        document.write("a.slice(0,2) is " + slicedArr + "<br>");
        //注意不包括 end 對應的元素
         //如果省略 end 將復制 start 之后的所有元素
        document.write("a.slice(1) is " + a.slice(1) + "<br>");
    </script>
</head>
<body>
</body>
</html>




輸出結果：
typeof arr is objectarr.length is 1a.length is 4arr.toString() is java,intel,microsoft
arr.concat(a,b) is java,intel,microsoft,2,6,5,a,12,14
arr.join() is java,intel,microsoft
arr.join(' & ') is java & intel & microsoft
arr.reverse() is microsoft,intel,java
arr.sort() is intel,java,microsoft
a is 2,6,5,a
a.slice(0,2) is 2,6
a.slice(1) is 6,5,a

例 1.4

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
    <script type="text/javascript">
        function sortNumber(a, b)
        {
            document.write(a + b);
        }
        function sortq(sortNumberqqq)
        {
            document.write("here");
            sortNumberqqq(1, 2);
            return 6;
        }
        /* 馬克-to-win：note that it will report error if we write the following statement as document.write("test "+sortq(sortNumberqixy));
       note that here sortNumber is a function pointer.
        */
        document.write("test " + sortq(sortNumber));
    </script>
</HEAD>

<BODY>

</BODY>
</HTML>

輸出結果：

here3test 6