為什么我點擊按鈕以后,h1和input標簽都消失了,代碼如下
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>字符</title>
</head>
<body>
<h1>消失</h1>
<input type="text" id="jhl" />
<input type="button" value="確定" onclick="ceui()">
<br /><br /><br /><br /><br />
<script type="text/JavaScript">
function ceui() {
var j = document.getElementById("jhl").value;
document.write("<br />"+j.length);
}
</script>
</body>
</html>
2016-06-28
document.write("<br />"+j.length);這句代碼
頁面加載完畢之后調用document.write的話會把文檔都完全覆蓋的