javascript imageslider setinterval

Question

var imagecount = 1;
var total = 3;

我想知道为什么我不能这样做imageslider。我保存了诸如studentbild1，studentbild2和studentbild3之类的图片。如何在setinterval这样显示这些内容。

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

删除内部双引号，用单引号替换它们：

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

给予

url("studentbild1.jpg")

等

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")';