Develop Reference

Textbox to accept decimal and negative as well as backspace using Jquery

I am trying to restrict text box to accepts only decimals,integers and also - (negative sign) as well as backspace I tried with below script but its not allowing - sign
$(document).ready(function() {
$('#MainContent_txtAmount').keypress(function(event) {
if ((event.which != 46 || $(this).val().indexOf('.') != -1) &&
((event.which < 48 || event.which > 57) &&
(event.which != 0 && event.which != 8))) {
event.preventDefault();
}
var text = $(this).val();
if ((text.indexOf('.') != -1) &&
(text.substring(text.indexOf('.')).length > 2) &&
(event.which != 0 && event.which != 8) &&
($(this)[0].selectionStart >= text.length - 2)) {
event.preventDefault();
}
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input id="MainContent_txtAmount" type="text" />
How can I accepts negative numbers too.

This allows the "-" sign too. Added && event.which != 45 . DEMO FIDDLE
$(document).ready(function () {
$('#MainContent_txtAmount').keypress(function (event) {
if ((event.which != 46 || $(this).val().indexOf('.') != -1) &&
((event.which < 48 || event.which > 57) &&
(event.which != 0 && event.which != 8)) && event.which != 45) {
event.preventDefault();
}
var text = $(this).val();
if ((text.indexOf('.') != -1) &&
(text.substring(text.indexOf('.')).length > 2) &&
(event.which != 0 && event.which != 8) &&
($(this)[0].selectionStart >= text.length - 2)) {
event.preventDefault();
}
});
});

Find the attached fiddle
sql fiddle demo
"-" has a charCode of 45.
change your condition event.which < 48 || event.which > 57 to
event.which != 45 && (event.which < 48 || event.which > 57)

isNumberKey() not working

A long time ago if found some code (on this site) that stopped the user from entering Letters into a text box, and it worked. Since finding this code I have changed it and added and now it doesn't work. This is what code I have:
var count = 1
function isNumberKey(event) {
var keyCode = window.event ? event.keyCode : event.which;
if (event.keyCode === 8 // backspace
|| event.keyCode === 46 // delete
|| event.keyCode === 13 // enter key
|| event.keyCode === 9 // tab
|| event.keyCode === 116 // F5 (refresh)
|| event.keyCode === 112 // F1
|| event.keyCode === 113 //F2
|| event.keyCode === 114 //F3
|| event.keyCode === 115 //F4
|| event.keyCode === 117 //F6
|| event.keyCode === 118 //F7
|| event.keyCode === 119 //F8
|| event.keyCode === 120 //F9
|| event.keyCode === 121 //F10
|| event.keyCode === 122 //F11
|| event.keyCode === 123 //F12
) {
return true;
}
else if ( key < 48 || key > 57) {
if (count < 6) {
count++; //adds one to count
}
else {
alert("Please Only Enter Numerical Values");
count = 1;
}
return false;
}
else return true;
}
I'm not claiming I made/wrote this code but can anyone see any problems with the code?

This will work. It was not working because you use key < 48 || key > 57 instead event.keyCode < 48 || event.keyCode > 57
var count = 1
function isNumberKey(event) {
var keyCode = window.event ? event.keyCode : event.which;
if (event.keyCode === 8 // backspace
|| event.keyCode === 46 // delete
|| event.keyCode === 13 // enter key
|| event.keyCode === 9 // tab
|| event.keyCode === 116 // F5 (refresh)
|| event.keyCode === 112 // F1
|| event.keyCode === 113 //F2
|| event.keyCode === 114 //F3
|| event.keyCode === 115 //F4
|| event.keyCode === 117 //F6
|| event.keyCode === 118 //F7
|| event.keyCode === 119 //F8
|| event.keyCode === 120 //F9
|| event.keyCode === 121 //F10
|| event.keyCode === 122 //F11
|| event.keyCode === 123 //F12
) {
return true;
}
else if ( event.keyCode < 48 || event.keyCode > 57) {
if (count < 6) {
count++; //adds one to count
}
else {
alert("Please Only Enter Numerical Values");
count = 1;
}
return false;
}
else return true;
}

this should do it:
textBox.onkeypress = function(e) {
e = e || window.event;
var charCode = (typeof e.which == "undefined") ? e.keyCode : e.which;
var charStr = String.fromCharCode(charCode);
if (/\d/.test(charStr)) {
return false;
}
};

This came up when I was asking, so it might be worth adding here that keyCode and charCode is deprecated, as at this time, so the accepted answer might not be the best.
A better way of adding the check or implementing the isNumberKey function could be:
const isNumberKey = (event: KeyboardEvent) =>
((event.key.length > 1) || event.key.match(/^\d|-$/))
This way, we check allow special keys do their function, while making sure only numbers are allowed when single character keys are pressed.

CheckNumeric value in JavaScript

I have this function for checking text box value for entering only integer values.
function CheckNumeric(e) {
if (window.event) // IE
{
if ((e.keyCode < 48 || e.keyCode > 57) & e.keyCode != 8) {
event.returnValue = false;
return false;
}
}
else { // Fire Fox
if ((e.which < 48 || e.which > 57) & e.which != 8) {
e.preventDefault();
return false;
}
}
}
In this function textbox can accept 0 for value and reject any character.
Now I want to change this function to reject 0 if it is entered as the first character.
For example reject this: 010 and accept this: 10

you need to check if (e.keyCode == 48 && input.value.length == 0) then return false;
input is your text box element.
something like this
if (window.event) // IE
{
if (((e.keyCode < 48 || e.keyCode > 57) & e.keyCode != 8) || (e.keyCode == 48 && input.value.length == 0)) {
event.returnValue = false;
return false;
}
}
and it should be
(e.keyCode < 48 || e.keyCode > 57) && e.keyCode != 8)
instead of
(e.keyCode < 48 || e.keyCode > 57) & e.keyCode != 8)

event.keycode issue

i have a javascript code like below,
if (event.keycode != 37 && event.keycode != 39)
{
var phoneNumber = $('#phoneNumber').val();
if (phoneNumber.length < 1 && event.keyCode != 48)
$('#phoneNumber').val(0)
else if ((phoneNumber.length < 2 && event.keyCode == 48) )
event.preventDefault();
else
$('#phoneNumber').val(phoneNumber)
}
keycode 37 = left arrow, keycode 39 = right arrow but when i pressed these keys on keyboard condition which is between if block being executed, i am using chrome browser, also i used the if statement below,
if (event.keycode != 37 || event.keycode != 39)
{
var phoneNumber = $('#phoneNumber').val();
if (phoneNumber.length < 1 && event.keyCode != 48)
$('#phoneNumber').val(0)
else if ((phoneNumber.length < 2 && event.keyCode == 48) )
event.preventDefault();
else
$('#phoneNumber').val(phoneNumber)
}
urgent helps greatly appreciated,
Thanks everybody.

One issue is capitalization: it's keyCode, not keycode. Your code is using them inconsistently.

focus at the end of the text in a textbox

i have a requirement: a text box can have a max of 50 characters, to achieve this I gave preventDefault.
if (!(event.ctrlKey && (event.which == 65 || event.which == 86 || event.which == 67 || event.which == 88))
&& (!(event.shiftKey && (event.which == 35 || event.which == 36)))
&& (key != 8 && key != 37 && key != 39 && key != 46 && key != 36 && key != 35 && key != 33 && key != 34)) {
event.preventDefault();
}
But now the requirement is : when we press ctrl+a and then abc it should erace everything from the text and print abc.
to achieve this i wrote this code ->
var focusItem = $('<input type="text">');
function getSelText() {
var txt = '';
//IE
var focusItem = $('<input type="text">');
if (document.selection != undefined) {
focusItem.focus();
var sel = document.selection.createRange();
var rangeParent = sel.parentElement();
txt = sel.text;
if (!(event.ctrlKey && (event.which == 65 || event.which == 86 || event.which == 67 || event.which == 88))
&& (!(event.shiftKey && (event.which == 35 || event.which == 36)))
&& (key != 8 && key != 37 && key != 39 && key != 46 && key != 36 && key != 35 && key != 33 && key != 34)) {
//event.preventDefault();
if (txt.length > 0 && ((key >= 65 && key <= 90) || (key >= 48 && key <= 57) || (key >= 97 && key <= 122))) {
sel.text = String.fromCharCode(key).toLowerCase();
}
txt = sel.text;
}
}
return txt;
}
now things are working but.. when I press ctrl+a abc then its getting printed as bca. Whats happening is : When i press a after ctrl+a then a is getting printed on the textbox but the focus is getting set before the text, that is a.
How to deal with this.
I am using windows 7, IE9, visual studio 2010.
Thanks.

The easiest way to set the focus to the end of a textbox is to just set the text of the textbox to itself:
focusItem.val(focusItem.val());