Develop Reference

Keycode value is return as 229 for all keys

I have run the normal textbox in android device an i have face some issues which is mentioned below.
1.Keypress event does not triggered in android device
2.keycode value always return as 229 only
How to resolve this issue?

Normal keypress event does not give keyCode in android device. There has already been a big discussion on this.
If you want to capture the press of space bar or special chars, you can use keyup event.
$('#input').on('keyup', e => {
var keyCode = e.keyCode || e.which;
if (keyCode == 0 || keyCode == 229) {
keyCode = e.target.value.charAt(e.target.selectionStart - 1).charCodeAt();
}
})

just check your input characters keyCode, if it is 0 or 229 then here is the function getKeyCode which uses charCodeAt of JS to return the KeyCode which takes input string a parameter and returns keycode of last character.
<script>
var getKeyCode = function (str) {
return str.charCodeAt(str.length);
}
$('#myTextfield').on('keyup',function(e){
//for android chrome keycode fix
if (navigator.userAgent.match(/Android/i)) {
var inputValue = this.value;
var charKeyCode = e.keyCode || e.which;
if (charKeyCode == 0 || charKeyCode == 229) {
charKeyCode = getKeyCode(inputValue);
alert(charKeyCode+' key Pressed');
}else{
alert(charKeyCode+' key Pressed');
}
}
});
</script>

Trying to validate a function in HTML

For my html, I'm trying to validate a form with a postcode input.
But this input is not working (or not being recognized). For my postcode input, I want to text box to only accept numbers.
Postcode input:
var Postcode = document.forms["Rego"]["postcode"].value;
var e = Postcode;
var code = e.keyCode;
if (code > 47 && code < 58) || code == 40 || code == 41 || code == 43) {
return true;
}
alert("Invalid Postcode. Please enter numbers only.");
return false;
What am I doing wrong?

In your condition if in line 4 after 58 why you close the ) ???

You are doing quite a few things wrong. You are not setting an event handler, you are actually binding to the value in the input box. You have to first get the DOM element representing the text box, then bind an event handler to the DOM element. Try this:
var Postcode = document.getElementById('post');
Postcode.onclick = function(e) {
console.log(e);
var code = e.keyCode;
if (code > 47 && code < 58 || code == 40 || code == 41 || code == 43) {
return true;
}
alert("Invalid Postcode. Please enter numbers only.");
e.preventDefault()
return false;
}
Fiddle: http://jsfiddle.net/S47gV/

To only accept numbers, you can use (for HTML5):
<input type="number" name="whatever">
Plus, if you want to validate it with js (doing so in browser is not recommended as anyone can modify your js file and push the contents to the server) or server code, here's some insight:
Try to convert the string passed to the server into a number. For example, in python you can do: int(whatever). If the conversion fails, that means the string isn't a number.
Hope that helps :)

If you use HTML5 you can set this automatically.
<input type="number" name="quantity" min="47" max="58">

By using below code textbox/inputbox allow only numeric value
$j('#inputbox_id').keydown(function (e) {
if (e.shiftKey || e.ctrlKey || e.altKey) {
e.preventDefault();
} else {
var key = e.keyCode;
if (!((key == 8) || (key == 46) || (key >= 35 && key <= 40) || (key >= 48 && key <= 57) || (key >= 96 && key <= 105))) {
e.preventDefault();
}
}
});
and if you want to set length of textbox/input box then set "maxlength=5"

I think i have found what you are doing wrong:
You are reading postcode value from input type and then comparing its keycode.
However‚ it may work only when your input has single number and when you type more characters in it your postcode variable becomes something for example 5436 and then when you use keycode function on this in wont work as expected.

Backspace and space not working in Firefox

I have the following validation to allow only numbers and a decimal in Javascript
function validate(evt) {
var theEvent = evt || window.event;
var key = theEvent.keyCode || theEvent.which;
key = String.fromCharCode( key );
var regex = /[0-9]|\./;
if( !regex.test(key) ) {
theEvent.returnValue = false;
if(theEvent.preventDefault) theEvent.preventDefault();
}
}
I call this in my textbox element like onkeypress='validate(event)'
This code works fine in IE but when I try the same with Firefox backspace, left and right arrow keys and space does not work.
How would I fix this?

Using key press is the right solution, but you simply need to attach the event handler by JS (which is considered better practice anyway), and use something like this:
$('#myInput').keypress(function(event){
validate(event)
});
function validate(evt) {
var theEvent = evt || window.event;
var key = theEvent.keyCode || theEvent.which;
if (key <48 || key > 57 || key == 190)//keycode is a number between 0 and 9 or '.'
...
};

use keyup or keydown instead of keypress
keypress is only supposed to fire when there is a character insert
http://www.quirksmode.org/dom/events/keys.html

keydown function would work across all browsers. Please use keydown function and it would work!
Ex.:-
$(document).keydown(function (e){
if(e.keyCode == 37) // left arrow
{
//code for left arrow
}
else if(e.keyCode == 39) // right arrow
{
//code for right arrow
}
});

Try
//allows number and hyphen only
function isNumeric(e)
{
var a = e.charCode;
if(a==0){return;}
return ((a >= 48 && a <= 57));
}
</script>
Firefox Backspace charcode 0.

Jquery keypress except: {something}

Is there any shortcut( actually a function) in jQuery or Javascript to handle button press except something, or only something, e.g.:
$(input).keypress('nonfunctional' function(){
// do something
});
that will trigger only on [a-z][0-9] buttons pressed and ignoring single shift or ctrl but handling shift+a => A pressed?
P.S.i do know about if(key.code == 123) then ...

No, if you want to exclude specific keys that's what the event.keyCode / event.which properties are there for.

Or you can extend jquery keypress. Something like this I guess:
$.fn.keypressBut = function(codes, callback) {
$(this).keypress(function(e) {
~$.inArray(e.keyCode, codes) || callback.call(this, e);
});
}
// Lets ignore Enter and Space
$('input').keypressBut([13, 32], function(e) {
alert(e.keyCode);
})

You could do something like
Extend jquerys fn propertie with a function which takes params like
Some Data
A callback function
Write a validation Function which
Converts the keyCode to a String
Match it against a Regular Expression.
If the shiftKey was Pressed
Convert it to Upper Case
Check if other Conditions, like Ctrl/Alt key Pressed are met.
Returns the Result.
If the validation succeeds
execute the callback function
On the code site this could like
$.fn.selectedKey = function (cb, data) {
def.call(data, {
ctrlKey: 2, //0: musn't be pressed, 1: must be pressed, 2: both.
altKey: 2, // "
invert: 0, //inverts the filter
filter: /.*/, // A Regular Expression, or a String with a Regular Expression
preventDefault: false //Set to true to prevent Default.
}); //Sets the default Data for the values used,
function validate(e) {
var key = e.char = String.fromCharCode(e.keyCode || e.which); // Converts the pressed key to a String
if (e.shiftKey) key = key.toUpperCase(); //Handles Case Sensitivity.
var exp = new RegExp(e.data.filter.replace(/\\\\(\d)/g, String.fromCharCode("$1"))); //Creates a new RegExp from a String to e.g. allow "\2" to match the keyCode 2
var c = !! (e.data.ctrlKey ^ e.ctrlKey ^ 1 > 0); //c == true if the above stated conditions are met e.g Ctrl Key Pressed and `ctrlKey == 1` -> true
var a = !! (e.data.altKey ^ e.altKey ^ 1 > 0); //e.g Alt Key Pressed and `altKey == 0` -> false
return (exp.test(key) && (c && a)); //Returns the validation Result
}
function def(obj) { //a minimal helper for default values
for (var prop in obj) {
this[prop] = this[prop] || obj[prop];
}
}
this.keypress(data, function (e) {
if (e.data.preventDefault) e.preventDefault();
if (validate(e) != e.data.invert) cb(e); //Calls the callback function if the conditions are met
});
};
Which you could then use the following ways
With a regex
$("body").selectedKey(function (e) {
console.log("All lower characters Numbers and 'A': " + e.char);
}, {
filter: /[a-z]|[0-9]|A/,
ctrlKey: 2,
altKey: 2
});
This would be triggered if any [a-z] or [0-9] or the Shift key + A has been pressed, regardless of the state of ctrl and alt
Or a keycode
$("body").selectedKey(function (e) {
// do somet
console.log("KeyCode 2 " + e.char);
}, {
filter: "\\2", //Ctrl + b
ctrlKey: 1,
altKey: 2
});
Would be triggered if you press ctrl +b
You could also combine those both.
Heres an Example on JSBin, to fiddle around with.

There is a jQuery plugin for using classes and regex for filtering keypresses if you dont want to write a large if statement to detect the key code pressed, its called keyfilter. An example would be
$(selector).keyfilter(/[a-z]/);

For example this function below allow only numbers en handle this functions using the keydown event.
function OnlyNumbers(event) {
if (event.keyCode == 46 || event.keyCode == 8 || event.keyCode == 9 || event.keyCode == 27 || event.keyCode == 13 || (event.keyCode == 65 && event.ctrlKey === true) || (event.keyCode >= 35 && event.keyCode <= 39)) { return; }
else { if (event.shiftKey || (event.keyCode < 48 || event.keyCode > 57) && (event.keyCode < 96 || event.keyCode > 105)) { event.preventDefault(); } }
}

have you tried event.altKey/event.shiftKey/event.ctrlKey ??

JavaScript Key Codes

I'm working with a JavaScript routine I didn't write. It is called from a text box's onkeydown attribute to prevent unwanted keystrokes.
The first argument is apparently not used. The second argument is a list of characters that should be allowed.
function RestrictChars(evt, chars) {
var key;
var keychar;
if (window.event)
key = window.event.keyCode;
else if (e)
key = e.which;
else
return true;
keychar = String.fromCharCode(key);
if ((key == null) || (key == 0) || (key == 8) ||
(key == 9) || (key == 13) || (key == 27))
// Control key
return true;
else if (((chars).indexOf(keychar) > -1))
return true;
else
return false;
}
This seems to work for alpha-numeric characters. However, characters such as . and / cause this function to return false, even when these characters are included in the chars parameter. For example, if the . key is pressed, key is set to 190, and keychar gets set to the "3/4" character.
Can anyone see how this was meant to work and/or why it doesn't? I don't know enough about JavaScript to see what it's trying to do.

Two things are wrong with that: first, if you're analysing what character has been typed, you need to use the keypress event instead of keydown because that is the only event that tells you anything reliable about the actual character typed. For (a lot) more detail about about this and JavaScript key events in general, see http://unixpapa.com/js/key.html. Second, there are references to a variable called e which doesn't (but should) correspond with the evt parameter.
Here's a rewrite, assuming you have a variable called textBox that refers to the text input element.
jsFiddle: http://jsfiddle.net/9DZwL/
Code:
function isKeypressCharValid(e, chars) {
e = e || window.event;
// Allow delete, tab, enter and escape keys through
if (/^(8|9|13|27)$/.test("" + e.keyCode)) {
return true;
}
var charCode = (typeof e.which == "number") ? e.which : e.keyCode;
var charTyped = String.fromCharCode(charCode);
return chars.indexOf(charTyped) > -1;
}
textBox.onkeypress = function(evt) {
if (!isKeypressCharValid(evt, "abc123")) {
return false;
}
};

I'm not a JS person, either, but... I can explain how it's supposed to work; I don't know why you're getting the values you are for the keys you mentioned, however.
keychar = String.fromCharCode(key);
This checks to see if the key is a printable character (letter, punctuation mark, etc.)
if ((key == null) || (key == 0) || (key == 8) ||
(key == 9) || (key == 13) || (key == 27))
// Control key
The above checks to see if the key is null OR (||)` 0 or 8 (backspace) or 9 (tab) or 13 (0x0D, or ENTER) or 27 (0x1B or ESCAPE) - it's exactly the Boolean result you'd expect: IF <thiscondition> or <thatcondition> or <anothercondition> or ...
else if (((chars).indexOf(keychar) > -1))
This checks to see if the keychar is in the string of characters passed as the chars parameter