<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script>
window.onload = function(){
var oInp = document.getElementById("inp");
var oBtn = document.getElementById("btn");
oBtn.onclick = function(){
// oInp.value = "123123";//用点来实现
// oInp['value'] = "123213";//用中括号 里面是字符串
oInp.setAttribute('value',"123123");
}
}
</script>
</head>
<body>
<input type="text" />
<button >按钮</button>
</body>
</html>