html部分

js部分

<script>

var x1=document.getElementById('x1');

var x2=document.getElementById('x2');

var x3=document.getElementById('x3');

var x4=document.getElementById('x4');

var x5=document.getElementById('x5');

function getrandom(n,m){

return Math.round(Math.random()*(m-n)+n);

}

function fn(obj){

var x=getrandom(0,document.documentElement.clientWidth-100);

var y=getrandom(0,document.documentElement.clientHeight-100);

obj.style.left=x+'px';

obj.style.top=y+'px';

}

fn(x1);

fn(x2);

fn(x3);

fn(x4);

fn(x5);

window.setInterval(function (){

fn(x1);

fn(x2);

fn(x3);

fn(x4);

fn(x5);

},500);

</script>