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javascript select only portion of string on input focus

I have form with lot's of date input fields. I would only like to select firs two characters of date (e.g. day portion of the date only) when focusing on a input field. I have accomplished this with this code:
$(".date").focus(function() {
this.setSelectionRange(0, 2);
});
The problem is this only works if I focus on input field with a mouse click. But if moving between input fields with TABULAR key on keyboard then the entire text in input field is selected. Can this be controlled via JavaScript as well?
Here is also JSFiddle which demonstrates above.

It sounds like the default handler is being run after yours.
Prevent this by stopping the browser's default handler by running:
$(".date").focus(function(e) {
e.preventDefault();
this.setSelectionRange(0, 2);
});

i posted here an answer, which is related to what you want , check it out: how-to-select-particular-text-in-textbox

Making a text field uneditable and not just readonly

When i click on a textfield, i get a dropdown so the user could select a value from the list.
After the user selects the date from the dropdown, he/she could edit the date by even adding characters to it. So i want to find a way to prevent this. I thought of making the field un-editable. So i used readonly but, this prevents the user from clicking and displaying the list. So can someone tell me how can i make the field uneditable.
<input id="datePiccc" type="text" class="dates" />

You can use the below code. This will make the text input field clickable but when the user types in anything, nothing would happen.
document.getElementById('datePiccc').onkeydown = function(e){
e.preventDefault();
}
Fiddle Demo
As pointed out by nnnnnn, onkeydown is a better option than onkeypress as it would stop the delete and backspace key functions.
You could add the below also to your code to nullify Cut and Paste events1. (Note: Not doing anything for Copy as that operation isn't going to change the value of the text field).
document.getElementById('datePiccc').oncut = function(e){
e.preventDefault();
}
document.getElementById('datePiccc').onpaste = function(e){
e.preventDefault();
}
1 I think these should work in all browsers. Currently tested in Chrome 31, Opera 15, IE10 and FireFox 24. (Note: In IE10, there is an x mark which appears on the right side of the input field which when clicked clears the entire field value. Could not find a way around this.)

I'm assuming the text field is being set in javascript. If so, you can use the following line to disable the field:
document.getElementById('datePiccc').disabled=true;
The input will remain as it is and the value from the selection field can also be set.

Disable the input in JQuery as
$("#datePiccc").attr("disabled", true);
And in pure JS
document.getElementById('datePiccc').disabled = true;
May be this can help!

Grab text input as the user types

I'm trying to update a span tag on the fly with data from an input text field. Basically I have a text field and I'd like to be able to grab the user's input as they type it and show it to them in a span tag below the field.
Code:
<input id="profileurl" type="text">
<p class="url">http://www.randomsite.com/<span id="url-displayname">username</span></p>
JQuery:
var username;
$('#profileurl').keyup(function(username);
$("#url-displayname").html(username);
See it in JS Fiddle: http://jsfiddle.net/pQ3j9/
I'm guessing the keyup function is not the best way to do this. Since checking the key wouldn't be able to grab prefilled or pasted form input.
Ideally there is some magical jQuery function that can just output whatever info is in the box whenever it detects a key up but if that method exists I haven't found it yet.
EDIT: You guys are fricken amazing. It looks like .val() is that magic method.
Second question: How would you restrict input? Looking at the modified jsfiddle's, when a user inputs an html tag like < hr > the browser interprets it and breaks the form. Do you specify an array and then check against that? Does jquery have anything like PHP's strip_tags function?

$('#profileurl').keyup(function(e) {
$("#url-displayname").html($(this).val());
}).keypress(function(e) {
return /[a-z0-9.-]/i.test(String.fromCharCode(e.which));
});
check out the modified jsfiddle:
http://jsfiddle.net/roberkules/pQ3j9/5/
Update: As #GregL points out, keyup indeed is better, (otherwise e.g. backspaces are not handled at all).

Similar to roberkules' answer, but using keyup() like you proposed seems to work better for me in a Chrome-based browser:
$('#profileurl').keyup(function(e) {
$("#url-displayname").html($(this).val());
});
Updated jsFiddle: http://jsfiddle.net/pQ3j9/3/

For the second question, if you wish to maintain characters and not have them parsed as html entities then you should do this instead :
$('#profileurl').keyup(function(key) {
$("#url-displayname").text($(this).val());
});
Check it out at - http://jsfiddle.net/dhruvasagar/pQ3j9/6/

You can bind multiple events with bind
http://jsfiddle.net/dwick/DszV9/

Clean and accesible Other option (Check box and text box)

When I have a set of either check boxes or radio buttons I often need to have an Other choice. This check box or radio button is very often accompanied by a text box where the user is supposed to fill out what this Other is.
How do you usually handle this set up? What kind of markup do you use? What do you require in your validation? Do you use java script for anything? For example:
How do you make the form accessible? Do you use and how do you use the label tag, for example.
Do you connect the check box and text box in any way with some javascript? For example, do you activate the text box when the check box is checked? Do you check or uncheck the check box automatically if the text box is filled out or cleared?
Do you let validation fail with error messages if the check box is checked but the text box is not filled out, or if the text box is filled out but the check box is not checked? Or do you just consider it not filled out and not checked?
Very unsure how to best deal with this issue, so any advice and examples are most welcome c",)

Typically when I have dynamic forms, I insert the input dynamically. That is, in the case of jQuery, I'll use .append('<input...') or some other similar function to actually insert the elements, and id it (or class it, depending), so that it can be easily .remove()-ed if the user decides they want to use another option instead. Validation is either handled via an onClick on an input button. If I'm feeling feisty, I'll go the AJAX route, and skip the <form> altogether.
I would definitely let the validation fail. They want "Other", and you want to know what "Other" is. If you don't care what Other is, then don't bother with the input box.
Edit: Might look something like this.
$('input[type="radio"]').click( function() {
if($(this).next().attr('name') != 'other' && $(this).attr('name') == 'other_input') {
$(this).after('<textarea name="other"></textarea>');
} else {
$('textarea[name="other"]').remove();
}
}
The click will react to any radio being clicked, and the if will make sure that it's only the "other" radio button that will react to the click, and that it will only react if there isn't already a textarea after it (so you don't get multiple textarea propogations).
On the processing side of things, you'll have to do a validation at first to see if other was checked, and to grab the input of the textarea if it was. You should probably use server-side validation for that.
Hope that gets you started.

I usually enclose my radio buttons in a label like this:
<label><input type=radio value=xyz name=stjames>Saint James</label>
this way the user can click on the text to trigger the button.
When deciding how to behave, I usually say to myself "what do you think the user expected when they did that..." and that often gives me the answer. So, upon click or Focus of the text box, turn on the radio that goes with it. This won't work if you've disabled the text box!
( ) US ( ) UK (*) Other [________________]
If the Other choice is a dangerous one (deleting data), though, I'd disable the text box until the user explicitly clicks Other. Then, the Radio drives the Text Box instead of the other way around. You want the user to have to go through another step in this case. It depends on the situation - think about what'll happen in each case.
I usually try to make it impossible or annoying for the user to do something 'wrong'. EG disable the OK button if something is inconsistent. Or, select the Other radio when the user types in text. If there's text in the text box but the radio buttons are set to something different, I'd usually just ignore the text. But if it's a serious/dangerous situation, you want to make sure the user's made up their mind; if you delete the text when the user chooses a different radio, that might piss them off but it might be appropriate if they should be careful.

Adding inputs with AJAX?

Is there a way in AJAX or JS to add further inputs upon a button click?

In short, yes you can add more inputs on a button click.
For example, in jQuery, you could have something like this where the buttonID is the id attribute for the button and the formID is the id attribute for your form:
$("buttonID").click(function() {
//add new inputs here, something like:
$("formID").append('<input type="text" id="newInput" name="newInput" />');
});
You can also have the additional inputs hidden to start off with and then 'un-hide' them on a click if you want.

Further inputs? Run any JavaScript you want when a user clicks a button by adding an event listener to the button that listens for a click.

Once a user clicks on the button, if you have an event listener, you can change what they had entered, you can do anything anything you want.
I am not certain what you mean by 'further inputs' though. If you are sending data then you can append whatever you want, I frequently append a timestamp to help prevent caching issues, for example.