Question

Javascript和HTML

＆＃13;

$( document ).ready(function() {
    var inputMessage = $("#inputMessage");
    var sendButton = $("#sendButton");
    console.log(inputMessage.value); //->undefined
    inputMessage.value = "hello";
    console.log(inputMessage.value); //->"hello"

＆＃13;

<!DOCTYPE html>
<html lang="es">
<head>
	<title>Chat de Hernan</title>
	<!--jquery-->
	<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
	<script type="text/javascript" src="https://cdn.socket.io/socket.io-1.4.5.js"></script>
	<!--bootstrap-->
	<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" crossorigin="anonymous"></script>
	<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" crossorigin="anonymous">
	<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css" integrity="sha384-fLW2N01lMqjakBkx3l/M9EahuwpSfeNvV63J5ezn3uZzapT0u7EYsXMjQV+0En5r" crossorigin="anonymous">
</head>
<body>
	<div class="input-group">
		<input id="inputMessage" class="form-control" type="text" value="goodbye" placeholder="Escriba aqui">
		<span class="input-group-btn">
			<button id="sendButton" class="btn btn-default">Enviar</button>
		</span>
	</div>
	<!--js-->
	<script type="text/javascript" src="script.js"></script>
</body>
</html>

＆＃13;

我遇到的问题是未定义和＆＃34; hello＆＃34; 的值与再见的值不同

<input id="inputMessage" class="form-control" type="text" value="goodbye" placeholder="Escriba aqui">

这怎么可能？ value =＆＃34; goodbye＆＃34; 语句指出输入有一个＆＃34;再见＆＃34;值，但javascript表示它的值未定义，并且＆＃34; hello＆＃34;，respectibely。

Answer 1

您需要定位的属性：

inputMessage.attr('value')

https://jsfiddle.net/mark_c/ged56amh/

Answer 2

定义var inputMessage = $("#inputMessage");使inputMessage jQuery元素具有方法val()来获取/设置元素值。

因此，请使用inputMessage.val()或inputMessage.val('hello')来设置新值，而不是'inputMessage.value'。

Answer 3

这是因为您将输入作为jQuery对象获取，但您正在使用JavaScript函数。相反，请将value更改为val()。另外，请勿忘记关闭.ready。

＆＃13;

$( document ).ready(function() {
    var inputMessage = $("#inputMessage");
    var sendButton = $("#sendButton");
    console.log(inputMessage.val()); //->undefined
    inputMessage.val("hello");
    console.log(inputMessage.val()); //->"hello"
});

＆＃13;

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<!DOCTYPE html>
<html lang="es">
<head>
	<title>Chat de Hernan</title>
	<!--jquery-->
	<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
	<script type="text/javascript" src="https://cdn.socket.io/socket.io-1.4.5.js"></script>
	<!--bootstrap-->
	<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" crossorigin="anonymous"></script>
	<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" crossorigin="anonymous">
	<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css" integrity="sha384-fLW2N01lMqjakBkx3l/M9EahuwpSfeNvV63J5ezn3uZzapT0u7EYsXMjQV+0En5r" crossorigin="anonymous">
</head>
<body>
	<div class="input-group">
		<input id="inputMessage" class="form-control" type="text" value="goodbye" placeholder="Escriba aqui">
		<span class="input-group-btn">
			<button id="sendButton" class="btn btn-default">Enviar</button>
		</span>
	</div>
	<!--js-->
	<script type="text/javascript" src="script.js"></script>
</body>
</html>

＆＃13;

输入字段值不返回我预期的值

3 个答案: