如何指定這個隨機圖像腳本

Question

我有這個JavaScript來顯示在點擊一個隨機圖像：

function pickimg(){ 
var imagenumber = 4 ; 
var randomnumber = Math.random() ; 
var rand1 = Math.round((imagenumber-1) * randomnumber) + 1; 
images = new Array 
images[1] = "images/1.png" 
images[2] = "images/2.png" 
images[3] = "images/3.png" 
images[4] = "images/4.png" 
var image = images[rand1] 
document.randimg.src = image 

有沒有一種方法，以確保相同的圖像不連續出現兩次？

Answer 1

怎麼回合這個小alogrithm：

1. 存儲在所述陣列的時隙0的最後使用的圖像
2. 選擇隨機圖像索引爲大於0
3. 顯示它
4. 在槽與圖像替換它0

使用Javascript：

images = new Array(); 
images[0] = "images/1.png" //will be that last used image 
images[1] = "images/2.png" 
images[2] = "images/3.png" 
images[3] = "images/4.png" 
function pickimg(){ 
    var randomnumber = Math.random(); 
    // pick a random number from 1 to LENGTH (3) 
    var rand1 = Math.round((images.length-1) * randomnumber)+1; 
    var image = images[rand1]; //get the image 

    // switch so that the random image will be in the used 
    // images slot (slot 0) 
    images[rand1] = images[0] 
    images[0] = image 

    document.randimg.src = image 
}