<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
</head>
<body>
<span>aaaaaa</span>
<button>看不清</button>
</body>
<script>
var span = document.querySelector("span");
var button = document.querySelector("button");
button.onclick = function () {
var content =
"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
span.innerHTML =
content[getRandom(0, 61)] +
content[getRandom(0, 61)] +
content[getRandom(0, 61)] +
content[getRandom(0, 61)];
};
function getRandom(a, b) {
return parseInt(Math.random() * (b - a + 1)) + a;
}
console.log(getRandom(10, 100));
</script>
</html>