form表单中有下面的代码:
<form method="post" id="" action="">
<input type="text" id="username" name="username" />
<br>
<span id="namespan">username</span>
</form>
通过ID获取id值为username的文本框的方法为:
var username = document.getElementById("username").value;
通过id获取id值为namespan的标签的值的方法为:
var namespan = document.getElementById("namespan").innerHTML;
从以上可以看,文本框是通过value获取的值,标签是通过innerHTML获取的值;
同时,还可以通过innerHTML改变span的值:
var namespan = document.getElementById("namespan");
namespan.innerHTML="this is why we play";
那么span标签的值改变了,而且页面中显示的值也改变了
全部代码如下:
<html lang="en">
<head>
<script type="text/javascript">
function checkForm(){
var username = document.getElementById("username").value;
var info = document.getElementById("info").innerHTML;
var spaninfo = document.getElementById("namespan");
alert(username);
alert(info);
alert(spaninfo.innerHTML);
spaninfo.innerHTML="fuck you";
alert(spaninfo.innerHTML);
}
</script>
</head>
<body>
<form method="post" id="" action="">
<table>
<tr>
<td><input type="text" id="username" name="username" /></td>
<td><span id="namespan"></span></td>
</tr>
<tr>
<td><p id="info">this is why we play</p></td>
</tr>
</table>
<input type="button" value="click" οnclick="checkForm()"/>
</form>
</body>
</html>