<img src="1.jpg" class="img_edge">
<img src="1.jpg" class="img_edge">
<img src="1.jpg" class="img_edge">
var navbutton = document.querySelector('.nav_item');
navbutton.onclick = ()=>{
let imgURLs = ['img/bird.png','img/chineese.png','img/phone.png']
.sort(() => Math.random() - 0.5);
let imgs = document.getElementsByClassName("img_edge");
for (let i in imgs)
imgs[i].src = imgURLs[i];
}