documnet.getElementById does not fetch the value . what is going wrong?
i am sure this is quite a numb question to ask and most probably the most basic one. i am just a starter for JS.
i am trying to access the value of input field by document.getElementById and it is returning null to me i am not sure why here is the code.
<html>
<head>
<script type="text/javascript">
var name = document.getElementById("e_name");
alert(name);
</script>
</head>
<body>
<form action="" method="post">
<input type="text" name="name" id="e_name" value="Enter your Name"/>
<input type="submit" name="submit"/>
</form>
</bod开发者_运维知识库y>
</html>
the following code prints the value null in alert box. what is wrong?
Update :
When i use the following code.
<html>
<head>
</head>
<body>
<form action="" method="post">
<input type="text" name="name" id="name" value="Enter your Name"/>
<input type="submit" name="submit"/>
</form>
<script type="text/javascript">
var name = document.getElementById('name').value;
alert(name);
</script>
</body>
</html>
it prints Enter your Name but if i change the value it does not print the changed value. i would want to perform the following for validation purpose
a) holds the value of e_name in a javascript variable in the head tag
b) so that i should be able to process it for validation.
how do i do it?
Because you're calling that line of script even before document object is ready!
Try this
<body>
<form action="" method="post">
<input type="text" name="name" id="e_name" value="Enter your Name"/>
<input type="submit" name="submit"/>
</form>
<script type="text/javascript">
var name = document.getElementById("e_name").value;
alert(name);
</script>
</body>
Or this in your head tag.
<script type="text/javascript">
window.onload = function() {
var name = document.getElementById("e_name");
alert(name);
}
</script>
The Javascript code is executing before that HTML has loaded. The element with id="e_name" doesn't actually exist in the document yet.
加载中,请稍侯......
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