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jquery - allow only negative, positive or decimal number validation in field

I use this code for positive validation of numbers and decimal. Now I would like to allow also negative numbers and decimals but it is not working. Any idea please?
$('.number_only').keypress(function(e){
return isNumbers(e, this);
});
function isNumbers(evt, element)
{
var charCode = (evt.which) ? evt.which : event.keyCode;
if (
(charCode != 46 || $(element).val().indexOf('.') != -1) && // “.” CHECK DOT, AND ONLY ONE.
(charCode < 48 || charCode > 57)
)
return false;
return true;
}
I found this but no idea how to implement it jquery - allow only negative, positive or decimal number validation

You can use regex instead to solve your problem, change your method to something like this:
function isNumbers(evt, element)
{
var elementValue = $(element).val();
var regex = /^(\+|-)?(\d*\.?\d*)$/;
if (regex.test(elementValue + String.fromCharCode(evt.charCode))) {
return true;
}
return false;
}

Stopping Characters From Being Entered In Form Field

I want to restrict all symbols from being entered into my form fields in html.
Here is my code...
<script>
$('#location').keypress(function (e) {
var regex = new RegExp("[^a-zA-Z0-9]+$");
var str = String.fromCharCode(!e.charCode ? e.which : e.charCode);
if (regex.test(str)) {
return true;
}
e.preventDefault();
return false;
});
</script>
But that code does not allow any spaces or even using the delete key. I want everything to work but don't want any symbols (ie. $##%^!'"[]{}() etc...)

You could remove the invalid characters on keyup instead.
$('#location').keyup(function(e){
$(this).val($(this).val().replace(/[^a-zA-Z0-9\s]/g, '');
});
Otherwise you have to specify the keyCode of the keys you want to allow.
http://www.asciitable.com/

Just get the range of letters and numbers.
48 - 57 (0-9)
65 - 90 (A-Z)
97 - 122 (a-z)
<script>
$('#location').bind('keypress', function (e) {
if (e.which < 48 ||
(e.which > 57 && e.which < 65) ||
(e.which > 90 && e.which < 97) ||
e.which > 122) {
e.preventDefault();
}
});
</script>

Disable numeric keys

I have a little curiosity to understand, I've created a responsive site And I used 2 scripts to disable the numeric keys in an input field; The first does not allow the numbers to be entered,The second, a warning message appears that warns you that you can only type alpha characters, I would like to understand why on smartphones only work on firefox while on pc work perfectly:
This script disables the numeric keys:
enter code here
function Check(e) {
var keyCode = (e.keyCode ? e.keyCode : e.which);
if (keyCode > 47 && keyCode < 58) {
e.preventDefault();
}
}
And this makes the message appear:
$(document).ready(function(){
$(".inputTextBox").keypress(function(event){
var inputValue = event.which;
// allow letters and whitespaces only.
if(!(inputValue >= 65 && inputValue <= 123) && (inputValue != 32 && inputValue != 0)) {
event.preventDefault();
document.getElementById('warning07').style.display='block';
document.getElementById('07').innerHTML = "Inserire solo lettere!";
}
console.log(inputValue);
});
});
Can you explain me? Thanks in advance.

replace number and symbol with jquery/javascript

Does anyone know how can I replace the number and symbol (excluding dash and single quote)?
Example:
if I have a string "ABDHN'S-J34H##$";
How can I replace the number and symbol to empty and return me value "ABDHN'S-JH" ?
I have the following code to replay all the char and symbol to empty and only return me number
$(".test").keyup(function (e) {
orgValue = $(".test").val();
if (e.which != 37 && e.which != 39 && e.which != 8 && e.which != 46) {
newValue = orgValue.replace(/[^\d.]/g, "");
$(".test").val(newValue);
}
});

You should allow only letters, dash and single quotes, like this:
newValue = orgValue.replace(/[^a-zA-Z'-]/g, "");
Anything else will be replaced by "".

You can use this regex:
string.replace(/^[a-zA-Z'-]+$/, '')
The caret ^ inside a character class [] will negate the match. This regex will convert all characters other than a-z, A-Z, single quote and hyphen to empty

You could replace symbols by skipping them through keycode value on the keyboard.
Link for keycode values for reglar keyboard:
http://www.w3.org/2002/09/tests/keys.html
$("#your control").bind("keydown keyup", doItPlease);
function doItPlease(e)
{
// First 2 Ifs are for numbers for num pad and alpha pad numbers
if (e.which < 106 && e.which > 95)
{
return false; // replace your values or return false
}
else if (e.which < 58 && e.which > 47)
{
// replace your values or return false
} else {
var mycharacters = [8, 9, 33, 34, 35 // get your coders from above link];
for (var i = 0; i < mycharacters.length; i++) {
if (e.which == mycharacters[i]) {
// replace your characters or just
// return false; will cancel the key down and wont even allow it
}
e.preventDefault();
}

"ABDHN'S-J34H##$".replace(/[^\-'\w]/g, '')

"ABDHN'S-J34H##$".replace(/[0-9]|[\'##$]/g, "");

Javascript limit text input characters

I am wanting to restrict the input characters for a text box to [a-z0-9_-]. However whenever if do this buttons like backspace and the arrow keys don't work. I have found some attempts on this website and others but either they don't work properly on all browsers or they use a black list. For example the W3Schools website example black lists numbers. Is there a way to use white list (the one above) and still allow keys like backspace, arrows, home, end etc? Or do I have to add everyone of the key codes that match the keys I want to allow? I do something like this (this is shortened for simplicity).
EDIT - Added code
<input type="text" onkeypress="return checkInput();">
function checkInput(){
return /[a-z0-9_-]/gi.test(String.fromCharCode(window.event.keyCode));
}

Just change the regex in the example to something like this:
numcheck = /[^a-z0-9_-]/;
Or better yet, avoid the double negative with:
numcheck = /[a-z0-9_-]/;
return numcheck.test(keychar);
Then you can look up the keycodes of backspace, etc. and check for them too:
if (keychar === 8) return true;
...
Or even put them in your regex:
numcheck = /[a-z0-9_\x08-]/;

You haven't provided any code samples, so it's hard to be specific in a response, but as a general strategy, try this: instead of trying to whitelist characters that can be input while they are being typed in, validate the contents of the text box after every key stroke to make sure that it still contains valid characters. If it doesn't, remove the last character entered.
This approach will allow special keys like backspace, etc., while at the same time achieve what it sounds like you are really after: a valid value in the text box.

Yes you can limit the input of characters. For example create a function that checks what is going on, return true if everything is OK and false if not:
// return true for 1234567890A-Za-z - _
function InputCheck(e) {
if ((e.shiftKey && e.keyCode == 45) || e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57)) {
if (e.which == 45 || e.which == 95 || (e.which >= 65 && e.which <= 90) || (e.which >= 97 && e.which <= 122))
return true;
return false;
}
return true;
}
once you have the function, hook it into you input (this is with jQuery):
$('#InputID').keypress(InputCheck);
You can make as complicated a check as you want, for example this will allow for USD money values:
function InputCheck(e) {
if ((e.shiftKey && e.keyCode == 45) || e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57) && e.which != 46 && e.which != 36) {
return false;
}
// . = 46
// $ = 36
var text = $(this).val();
// Dollar sign first char only
if (e.which == 36 && text.length != 0) {
return false;
}
// Only one decimal point
if (e.which == 46 && text.indexOf('.') != -1) {
return false;
}
// Only 2 numbers after decimal
if (text.indexOf('.') != -1 && (text.length - text.indexOf('.')) > 2) {
return false;
}
return true;
}

You can press any key you like, as long as you keep the value from including anything
not in the white-list.
inputelement.onkeyup=function(e){
e=e || window.event;
var who=e.target || e.srcElement;
who.value= who.value.replace(/[^\w-]+/g,'');
}

Add this code to onkeypress event.
var code;
document.all ? code = e.keyCode : code = e.which;
return ((code > 64 && code < 91) || (code > 96 && code < 123) || code == 8 || code == 32 || (code >= 48 && code <= 57));
For browser compatibility, You can add
var k = e.keyCode == 0 ? e.charCode : e.keyCode;