<!DOCTYPE html>
<html lang="en">
<head>
<script type="text/javascript">
function createCode() {
var datas = ['A','B','C','D','E','F'];
var code = "";
for(var i = 0;i < 4;i++){
var index = Math.floor(Math.random()*datas.length);
code += datas[index];
}
var spanNode = document.getElementById("code");
spanNode.innerHTML = code;
}
function ready() {
createCode();
}
</script>
<meta charset="UTF-8">
<title>产生验证码</title>
</head>
<body onload="ready()">
<span id="code"></span><a href="#" onclick="createCode()">看不清,换一个</a>
</body>
</html>
重点:
1.onload,在js里面写一个function ready(),然后调用
防止找不到,因为刚开始运行时,无法找到id code
2.<span id="code"></span><a href="#" onclick="createCode()">看不清,换一个</a>
这句就是span里面不放东西,可以后来再放进去