How to access an HTML textbox from javascript? - javascript

How to access an HTML textbox by a javascript function?

Set ID property on text box and use document.getElementById() function... Example below:
<html>
<head>
<script type="text/javascript">
function doSomethingWithTextBox()
{
var textBox = document.getElementById('TEXTBOX_ID');
// do something with it ...
}
</script>
</head>
<body>
<input type="text" id="TEXTBOX_ID">
</body>
</html>

First you need to be able to get a DOM(Document Object Model) reference to the textbox:
<input type="text" id="mytextbox" value="Hello World!" />
Notice the id attribute, the textbox now has the id mytextbox.
Next step is to get the reference in JavaScript:
var textbox = document.getElementById('mytextbox'); // assign the DOM element reference to the variable "textbox"
This will retrieve a HTML Element by its id attribute. Note that those id's need to be unique, so you can't have two textboxes with the same id.
Now the final step is to retrieve the value of the textbox:
alert(textbox.value); // alert the contents of the textbox to the user
The value property contains the contents of the textbox, and that's it!
For more reference you might want to check out some stuff over at MDC:
GetElementByID Reference
Input Element Reference
A general overview of the DOM

Very simply, try this:
<!doctype html>
<html>
<head>
…
</head>
<body>
<form>
<input id="textbox" type="text" />
</form>
<script>
var textboxValue = document.getElementById("textbox").value;
</script>
</body>
The variable textboxValue would equal whatever you've typed into the textbox.
Remember you must place your script, if written as simply as this, after the textbox (input field) appears in your HTML, otherwise when the page first loads you'd get an error, because the script is looking for input field that has not yet been created by the browser.
I hope this helps!

Give your textbox an id attribute, and after, fetch it with document.getElementById('<textbox id>').

document.getElementById('textboxid').value
or
document.formname.textboxname.value

Related

Create/update variable from text input box

After trying multiple ways of what I want to do, which all failed, I'm asking here. This is probably pretty basic, but I just can't do it.
What I essentially want to do:
Create a variable
"Assign" a text box (value) to it
Automatically have the variable's content change to whatever is put into the text box
Potentially have the variable's value used somewhere else immediately
If the user had to press a button to update the element using the variable's value, that'd be OK, too, I just want to have this done.
Alright, I have to correct myself. Another try worked, with the result of 'undefined'.
<head>
<meta id="test3" charset="utf-8">
<link rel="stylesheet" href=".\css\Starter.css">
<title id="test1">TITEL</title>
<script>
function txtSet(txtInp) {
var txt = txtInp.value
document.getElementById('txtP').innerHTML = txt
}
</script>
</head>
<body>
<input type="text" id="txtInp" onkeyup="txtSet(txtInp.value)"></input>
<p id="txtP"></p>
</body>
Try this one:
<body>
<script>
var a = "";
function changeVariable(){
document.getElementById('demo2').value=document.getElementById('demo').value;
}
</script>
<input type="text" id="demo" onkeyup="changeVariable()"></input>
<input type="text" id="demo2"></input>
</body>
I think that you're searching for onkeyup if it's so: you can use as it follows:
In your html
<input type="text" name="name" id="id" onkeyup="yourFunction(this.value);">
and in your js file
var theVariable;
function yourFunction(theTextInTheTextBox){
theVariable = theTextInTheTextBox;
}
It could also be onkeypress or onkeydown events, just try the three to see which is the one that you're actually searching for. To see the difference between the three I advise you to take a look at this link

Call javascript from XForms action

I am experimenting with XForms and trying to dynamically load javascript, but cannot figure it out.
I am presenting a simple example - that is just an input field and button that loads the javascript:
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:xf="http://www.w3.org/2002/xforms"
xmlns:ev="http://www.w3.org/2001/xml-events" >
<head>
<title>Hello World in XForms</title>
<xf:model>
<xf:instance xmlns="">
<data>
<firstName/>
</data>
</xf:instance>
</xf:model>
<script type="text/javascript">
var myFunction = function(){
var name = document.getElementById("firstName").value;
alert("Hello " + name + "!");
}
</script>
</head>
<body>
<xf:label>Please enter your first name: </xf:label>
<xf:input ref="firstName" id="firstName">
</xf:input>
<br />
<xf:trigger>
<xf:label>Click me!</xf:label>
<xf:action ev:event="DOMActivate">
<xf:load resource="javascript:myFunction()" />
</xf:action>
</xf:trigger>
</body>
</html>
So in my script I am trying to get the value from the input box and then show an alert box with concatenated string. Currently, I get "Hello undefined!"
Do you have an idea how to get the value from the firstName xf:input with Javascript?
I know how to do it with XForms only, but this is sort of a proof of concept.
On a side note - I am using XSLTForms, so the XForms runs on the client.
Another hint might be in the fact that XSLTForms transforms the xf:input into several nested span elements with a <input type="text"> element, but that input element does not have a name or id.
With XSLTForms, there are different possibilities...
If you want to access the value of the corresponding HTML input, I would suggest document.getElementById("firstName").xfElement.input.value.
You could also use the node property to get the value stored in the bound node.
Don't hesitate to browse DOM with a debugger to find how to get things from XSLTForms!
--Alain

Create unique name for <input> in form

Okay, first thing, I had a lot of trouble thinking of a title for this, and also of what to search for in Google. So that may just be me being stupid, but here is what I would like you help with.
I have a form, that has a button that will add additional input fields, but I would like the the name of the field to iterate everytime the button is pressed. E.g. the first time it will be:
<input type="textfield" name="field1" value=""/>
Then the second time it is pressed, it will be:
<input type="textfield" name="field2" value=""/>
I also have a small example of what I currently have here: http://jsfiddle.net/5gh75/14/
Please let me know if you can help me, or if you require more info thanks :)
The best way to handle this is to name them all field[].
When handled by the server-side code, it will build an array for you. For instance, in PHP you would get $_POST['field'][0], $_POST['field'][1] and so on.
For your example:
JQuery
var i=0;
$('span.add').click(function () {
$('<input>').attr({
type: 'textfield',
name: 'program'+i
}).appendTo('#addsoftware');
i++;
});
JSFiddle.
But #Kolink-s answer is much better.
Edit: I just saw the previous posts after sending this. Using an array would definitely be better, and JQuery is always nice :).
Just use some javascript:
<HTML>
<HEAD>
<TITLE>Dynamically add Textbox, Radio, Button in html Form using JavaScript</TITLE>
<SCRIPT language="javascript">
idx = 0;
function add() {
//Create an input type dynamically.
var element = document.createElement("input");
//Assign different attributes to the element.
element.setAttribute("type", "textfield");
element.setAttribute("name", "field" . idx);
element.setAttribute("value", "");
idx++;
var foo = document.getElementById("fooBar");
//Append the element in page (in span).
foo.appendChild(element);
}
</SCRIPT>
</HEAD>
<BODY>
<FORM>
<H2>Dynamically add element in form.</H2>
Select the element and hit Add to add it in form.
<BR/>
<INPUT type="button" value="Add" onclick="add()"/>
<span id="fooBar"> </span>
</FORM>
</BODY>
</HTML>
I took this example from: Add more text fields dynamically in new line (html)

Onchange Event in Javascript; How to input diffrent items

I am fairly new to javascript and I am 13. So I am new to events in javascript. I would like help on this code:
<head>
<script>
function myFunction()
{
var x=document.getElementById("fname");
if (x=="Kyle")
{
document.write("Correct!");
}
else
{
document.write("Incorrect!")
}
}
</script>
</head>
<body>
Enter your name: <input type="text" id="fname" onchange="myFunction()">
</body>
I want it to say correct when I type my name. Please help. Thanks
the line
if (x=="Kyle")
should read
if (x.value=="Kyle")
x represents the element, not the element's value.
I hope this helps. Feel free to ask if you have any other problems.
First create a div tag below your form and give it an id of something like "messageBox"
so:
<div id="messageBox"></div>
then replace
document.write("Correct!");
with
document.getElementById('messageBox').innerHTML = "Correct!";
and the same for incorrect.
All this does is create a div tag so that the javascript has somewhere to output the success/failure message.
You were oh so very close. You get the DOM element (getElementById), but you need to get the actual value of the element. Use x.value == "Kyle"

Setting HTML textbox value using javascript function?

I'm using this code to set the HTML textbox value using Javascript function. But it seems to be not working. Can anyone point out, what is wrong with this code?
Whats your Name?
<input id="name" value="" />
<script type="text/javascript">
function setValue(value){
var myValue=value;
document.getElementsById("name").value = myValue;
}
</script>
the "value" is came from my android java class using this codes
String value = "Isiah";
WebView web = (WebView) findViewById(R.id.web1);
web.getSettings().setJavaScriptEnabled(true);
web.loadUrl("file:///android_asset/www/webpage");
web.loadUrl("javascript:setValue("+ value +")");
function setValue(value) {
var myValue=value; //unnecessary
document.getElementById("name").value= myValue;
}
But then as pointed out in the comments, you need to call setValue(value) somewhere in your code. Right now you just defined the function is never called.
You could either access the element’s value by its name:
document.getElementsByName("textbox1"); // returns a list of elements with name="textbox1"
document.getElementsByName("textbox1")[0] // returns the first element in DOM with name="textbox1"
So:
input name="buttonExecute" onclick="execute(document.getElementsByName('textbox1')[0].value)" type="button" value="Execute" />
Or you assign an ID to the element that then identifies it and you can access it with getElementById:
<input name="textbox1" id="textbox1" type="text" />
<input name="buttonExecute" onclick="execute(document.getElementById('textbox1').value)" type="button" value="Execute" />
You are using document.getElementsById("name") it should be document.getElementById("name")
not Elements it is Element
You are not linking the function to anything. For example, a click:
<input id="name" value="" onclick="javascript:this.value=12;"/>
Replace the onclick attribute for your desired function, whatever it does (you need to be more specific)
Also, there is no language attribute (at least not anymore) use type="text/javascript" instead
Here is a fiddle: http://jsfiddle.net/4juEp/
Click the input to see it working.
Look at this second fiddle. http://jsfiddle.net/4juEp/1/
which loads whatever is defined in the hid input to the name input.
Firstly, you have a typo in your javascript function i.e. you have used getElementsById as compared to getElementById
To set the value of the textbox on page load, I suggest you use an alternative
<body onload="setValue('yourValueToSet');">
<!-- Your usual html code in the html file -->
</body>
I think you are missing the quotes,
try,
web.loadUrl("javascript:setValue('"+ value +"')");
also consider about the typo.
Check this out:
<body onload="setvalue($value);">
Whats your Name?<input id="name" name="name" value=""/>
<script type="text/javascript">
function setValue(value){
document.{formname}.name.value = value;}</script>
It's not Elements
It's Element
You should use document.getElementById('object-id');

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