作业:<input id="study" value="666"> 用js获取input的值，有一个按钮叫弹出，点击弹出，展示出input中的value的值？
解答：
- 按钮：
<input type="button" value="弹出" id="button"> - 获取页面的按钮：
document.getElementById("button") - 给按钮绑定事件：
元素onclick= function(){ 执行事件 } - 获取值：
document.getElementById("study").value
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>Examples</title>
<meta name="description" content="">
<meta name="keywords" content="">
<link href="" rel="stylesheet">
<style type="text/css">
</style>
</head>
<body>
<input id="study" value="666">
<input type="button" value="弹出" id="button">
<script>
document.getElementById("button").onclick = function () {
alert(document.getElementById("study").value)
}
</script>
</body>
</html>
引入变量：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>Examples</title>
<meta name="description" content="">
<meta name="keywords" content="">
<link href="" rel="stylesheet">
<style type="text/css">
</style>
</head>
<body>
<input id="study" value="666">
<input type="button" value="弹出" id="button">
<script>
var button = document.getElementById("button")
var study = document.getElementById("study")
button.onclick = function () {
alert(study.value)
}
</script>
</body>
</html>
