I just started learning JavaScript and am wondering why this simple snippet hangs when I click on the "Call function" button. What am I missing?
<html>
<head>
<script type="text/javascript">
function myfunction()
{
document.write("hello");
}
</script>
</head>
<body>
<form>
<input type="button"
onclick="myfunction()"
value="Call function">
</form>
</body>
</html>
You need to write inside an element or give an element a value, or you should use document write like that :
<html>
<head>
<script type="text/javascript">
function myfunction()
{
document.getElementById("lblMessage").innerText = "hello";
document.getElementById("txtMessage").value = "hello";
//document.write("hello");
}
</script>
</head>
<body>
<form>
<script type="text/javascript">
document.write("This is written while page processed by browser !<br />");
</script>
<input type="text" id="txtMessage" /><br />
<span id="lblMessage"></span><br />
<input type="button"
onclick="myfunction()"
value="Call function">
</form>
</body>
</html>
If you simply want to see your button doing something then try:
alert("Hello");
instead of the document.write.
Where do you expect the function to output its "hello"? Right into the button's source code? That makes no sense. The browser is confused and hangs.
Document.write doesn't magically insert something at the end of your document. It writes its stuff out right there where it is called.
Not too sure what you mean by "hang"... Try this out... The alerts can be removed, but will inform you of where it is at in execution...
<html>
<head>
<script type="text/javascript">
function myFunction() {
//for debugging
alert('Made it into function');
document.getElementById('MyOutputDiv').innerHTML = 'Word To Your Mom...';
//for debugging
alert('function complete');
}
</script>
</head>
<body>
<input type='button' onclick='myFunction();' value='Call Function'>
<br>
<div id='MyOutputDiv'></div>
</body>
</html>
document.write, but where? You have to specify this.
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Hello</title>
</head>
<body>
<pre><script type="text/javascript">
function myfunction() {
d = document.getElementById('hello');
d.style.display = "block";
d = document.getElementById('callme');
d.style.display = "none";
}
</script>
</pre>
<div id="hello" style="display:none">
Hello
</div>
<div id="callme">
<input type="button"
onclick="myfunction()"
value="Call function">
</input>
</div>
</body>
</html>
I can't explain the "hang" but please take a look at this page for a primer on document.write: http://javascript.about.com/library/blwrite.htm I would also like to second that you probably want to write to a specific element in the page rather than just overwriting the entire page.
Related
I was asked to develop a web page without a mouse.
The keyboard cursor must be in the input area(example: <input id="input-label" type="text">) immediately when the page is changed.
I tried,
document.querySelector("#input-area").focus();
and
document.querySelector("#input-area").select();
It works with buttons, but does not work in DOMContentLoaded.
document.addEventListener("DOMContentLoaded", function(){
document.querySelector("#input-area").select();
});
How can I solve it?
try this, call it when dom is ready
$(document).ready(function () {
$("#input-area").focus();
});
OR
<input id="input-area" autofocus="autofocus" />
OR
$(function() {
$("#input-area").focus();
});
Try this code:
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.3.1.js"></script>
<script>
$(document).ready(function(){
$('#myAnchor').click(function() {
$('#mustfocus').focus();
});
});
</script>
</head>
<body>
<input type="button" id="myAnchor" value="Get focus">
<input type="text" id="mustfocus"/>
</body>
</html>
How about this one which triggers only during DOM is ready:
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.3.1.js"></script>
<script>
$(document).ready(function(){
$('#mustfocus').focus();
});
</script>
</head>
<body>
<input type="button" id="myAnchor" value="Get focus">
<input type="text" id="mustfocus"/>
</body>
</html>
Although I know a lot about these languages now such as arrays and functions, I'm having a basic problem to getting this JavaScript to run, here's the code:
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<input type="submit" value="submit" onclick="click()" />
<script>
function click() {
alert("hey");
}
</script>
</body>
</html>
You're running into this problem: javascript function name cannot set as click?
You can fix this by changing the function name to something else like function myClick
<head>
</head>
<body>
<input type="submit" value="submit" onclick="myClick()" />
<script>
function myClick() {
alert("hey");
}
</script>
</body>
</html>
yes,like the comment above. you should use a different name instead of click()
function submit() {
alert("hey"); }
<html>
<head>
</head>
<body>
<input type="submit" value="submit" onclick="submit()" />
</body>
</html>
I want the data in the text field to transfer to a popup, but when I trigger the popup, it is always blank, no matter what is in the box.
<html>
<head>
<title>Popup</title>
</head>
<body>
<button onclick="popup()">Click for popup</button>
<input type="text" name=popupMess><br>
</body>
<script>
function popup() {
window.confirm(name.popupMess);
}
</script>
</html>
<html>
<head>
<title>Popup</title>
</head>
<body>
<button onclick="popup()">Click for popup</button>
<input id="popupMess" type="text"><br>
</body>
<script>
function popup() {
alert(document.getElementById('popupMess').value);
}
</script>
</html>
You forgot the " in name="popupMess".
function popup () {
var text = document.querySelector("input[name='popupMess']").value;
window.confirm(text);
}
Hi here is my jsfiddle that demonstrates the functionality
http://jsfiddle.net/7pjqfcvd/2/
you have to
mark the input element with an Id
<input type="text" id="popupMess"/>
use the id in document.getElementById call to obtain the input element
var elem = document.getElementById("popupMess");
retrieve the value from the element and pass it into the messagebox
window.confirm(elem.value);
But still if you want to use name then try this...
<html>
<head>
<title>Popup</title>
</head>
<body>
<button onclick="popup()">Click for popup</button>
<input type="text" name=popupMess><br>
<script>
function popup() {
var d = document.getElementsByName("popupMess");
window.confirm(d[0].value);
}
</script>
</body>
</html>
I have the following code that works:
<html>
<head>
<script>
function loaded(){
oFormElement = document.forms['test form'].elements["txtStatus"];
oFormElement.value = "just loaded";
}
</script>
</head>
<body onload="loaded()">
<p>my first socket.io test</p>
<form id = "test form">
<input type="text" id ="txtStatus" value="">
</form>
</body>
</html>
now, if I include the reference to socket.io, it stops working
<html>
<head>
<script src="socket.io/socket.io.js">
<script>
function loaded(){
is this because socket.io handles from elements in it's own way, or is because the browser cannot find socket.io ? Is there any way to debug this/fix this ?
You need to close the first <script> tag...
<html>
<head>
<script src="socket.io/socket.io.js"></script>
<script>
function loaded(){
// ...
please look at the following sample code:
<html>
<head>
<script type="text/javascript">
function myfun()
{
alert('hi');
}
</script>
</head>
<body>
<h1> Hello </h1>
<input type="button" value="MyButton" onClick="myfun()"/>
</body>
</html>
When I run this using php, and when I click on the button, the alert box doesn't come up. However, if I write onclick="alert(hi')" it works fine. What might be the reason?
<html>
<body>
<h1> Hello </h1>
<input type="button" value="MyButton" onClick="alert('hi')"/>
</body>
</html>
Missing a ' in your code...