javascript imageslider setinterval

Question

var imagecount = 1;
var total = 3;

I'd like to know why I can't make an imageslider this way. I have pictures saved such as studentbild1 , studentbild2 and studentbild3 . How do I get those to show in a setinterval like this.

window.setInterval(function slideA() {
    var image = document.getElementById('studentbild');
    imagecount = imagecount + 1;
    if(imagecount > total){ imagecount = 1;}
    if(imagecount < 1){ imagecount = total;}
    image.style.backgroundImage = 'url("studentbild" + imagecount + ".jpg")';
},1000);

Answer 1

Remove the inner double-quotes, replace them with single quotes:

image.style.backgroundImage = 'url("studentbild' + imagecount + '.jpg")';

to give

url("studentbild1.jpg")

etc.

 var imagecount = 0; var total = 3; window.setInterval(function slideA() { var image = document.getElementById('studentbild'); imagecount = imagecount + 1; if (imagecount > total) { imagecount = 1; } if (imagecount < 1) { imagecount = total; } image.style.backgroundImage = 'url("http://placehold.it/' + imagecount + '00")'; }, 1000); 

 #studentbild { width: 300px; height: 300px; } 

 <div id="studentbild"></div> 

Answer 2

解决此问题（在加号附近添加单引号）

image.style.backgroundImage = 'url("studentbild' + imagecount + '.jpg")';