Develop Reference

Need help restricting a js function(that restricts invalid chars) to a particular input type

Hi i would like to restrict a function that allows only, numbers, back space and left & right arrow keys to inputs with number type, because when i implement it, it also affects my text inputs.
<script>
function chars(evt){
var key = window.event ? event.keyCode : event.which;
if (event.keyCode == 8 || event.keyCode == 46
|| event.keyCode == 37 || event.keyCode == 39) {
return true;
}
else if ( key < 48 || key > 57 ) {
return false;
}
else return true;
}
</script>

Assign an id to your <input>. Add an event listener to it, like :
function getKeyCode() {
var key = window.event ? event.keyCode : event.which;
if(event.keyCode == 8 || event.keyCode == 46
|| event.keyCode == 37 || event.keyCode == 39) {
console.log(true);
//return true;
} else if (key < 48 || key > 57) {
console.log(false);
// return false;
} else {
console.log(true);
// return true;
}
}
var el = document.getElementById("myInput");
el.addEventListener("keypress", getKeyCode);
<input type="text" id="myInput">

How to restrict a field to take only 4 numeric characters as input and get's an alert in div

I wanted a text field to take only numbers as some control keys and number should be exactly four digit long. My code is as Follows:
<div id="main" role="main">
Input a 4-digit: <input type="text" class="validateYearTextBox" />
</div>
<div id="alert"></div>
function checkValidInput() {
$(".validateYearTextBox").keydown(function(event) {
if (!((event.keyCode == 46 ||
event.keyCode == 8 ||
event.keyCode == 37 ||
event.keyCode == 39 ||
event.keyCode == 9) ||
$(this).val().length < 4 &&
((event.keyCode >= 48 && event.keyCode <= 57) ||
(event.keyCode >= 96 && event.keyCode <= 105)))) {
// Stop the event
event.preventDefault();
return false;
}
});
}
$(document).ready(function() {
checkValidInput();
});
when I enter a 4 digit in the text box a alert should be appear in div as "valid"
this is the Fiddle

Try this:
Jsfiddle: https://jsfiddle.net/jz1ra36d/
just add:
$(".validateYearTextBox").keyup(function(event) {
if( $(this).val().length == 4){
$("#alert").text("valid")
} else {
$("#alert").text("")
}
});

JSFiddle
Try following:
<div id="main" role="main">
Input a 4-digit: <input type="text" class="validateYearTextBox" />
</div>
<div id="alert"></div>
<script>
function checkValidInput() {
$(".validateYearTextBox").keydown(function(event) {
if (!((event.keyCode == 46 ||
event.keyCode == 8 ||
event.keyCode == 37 ||
event.keyCode == 39 ||
event.keyCode == 9) ||
$(this).val().length < 4 &&
((event.keyCode >= 48 && event.keyCode <= 57) ||
(event.keyCode >= 96 && event.keyCode <= 105)))) {
// Stop the event
event.preventDefault();
return false;
}
// count number of characters entered
var cs = $('.validateYearTextBox').val().length;
if(cs == 3)
{
$('#alert').html('valid');
}
else
{
$('#alert').html('');
}
});
}
$(document).ready(function() {
checkValidInput();
});
</script>

You can use regular expression for it and change to keyup event:
function checkValidInput() {
var re = /\d{4}/g,
dt = $('.validateYearTextBox'),
msg;
msg = re.test(dt.val()) ? "Valid" : "Invalid";
$('#alert').text(msg);
}
$(".validateYearTextBox").keyup(checkValidInput);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="main" role="main">
Input a 4-digit:
<input type="text" class="validateYearTextBox" />
</div>
<div id="alert"></div>

I would do something like this.
function checkValidInput() {
$(".validateYearTextBox").keydown(function(event) {
if( $(this).val().length == 3){
$('#alert').html('<p>SUCCESS</p>');
}
if (!((event.keyCode == 46 ||
event.keyCode == 8 ||
event.keyCode == 37 ||
event.keyCode == 39 ||
event.keyCode == 9) ||
$(this).val().length < 4 &&
((event.keyCode >= 48 && event.keyCode <= 57) ||
(event.keyCode >= 96 && event.keyCode <= 105)))) {
// Stop the event
event.preventDefault();
return false;
}
});
}
$(document).ready(function() {
checkValidInput();
});

Try this simple script after adding onblur="checkValidInput" id="validateYearTextBox" to input tag
function checkValidInput(){
var x,text;
x=document.getelementbyid("validateYearTextBox").value;
if(x==4)
text="Valid";
else
text="Not valid";
}
document.getelementbyid("alert").innerHTML=text;

JQuery : Keypress not working on first press

This is my code
$(currentClass).keypress(function (e) {
if (e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57)) {
return false;
}
});
The only problem with this is that, every time I hit a key for the first time regardless a letter or a number, it shows up in my content editable span tag. However, the second time I hit a letter key the code works, it only accepts number. I have no idea what is wrong with this code in the first pressing of keys.

Use JQuery's .on() method.
$(currentClass).on("keypress",function (e) {
if (e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57)) {
return false;
}
});

This is what I used
if ($.inArray($event.keyCode, [46, 8, 9, 27, 13, 110, 190]) !== -1 ||
// Allow: Ctrl+A
($event.keyCode == 65 && $event.ctrlKey === true) ||
// Allow: home, end, left, right
($event.keyCode >= 35 && $event.keyCode <= 39)) {
// let it happen, don't do anything
return;
}
// Ensure that it is a number and stop the keypress
if (($event.shiftKey || ($event.keyCode < 48 || $event.keyCode > 57)) && ($event.keyCode < 96 || $event.keyCode > 105)) {
$event.preventDefault();
}
I was able to solve the problem with this. If their suggestion is not working try this.

Bind Properly your events
$(document).ready(function(){
$(body).on("keypress","currentClass",function (e) {
if (e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57)) {
return false;
}
});
});

$(currentClass).on('keypress', function (e) {
if (e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57)) {
e.preventDefault();
alert("pressed");
return false;
}
});
event - on
This might helps you :)

Restrict to input minus symbol

I need to restrict user to input minus symbol. How to do it useing following jQuery I have got?
$("#Age").keydown(function (e) {
// Allow: backspace, delete, tab, escape, enter
if ($(this).val().length <= 2 || $.inArray(e.keyCode, [46, 8, 9, 27, 13, 110]) !== -1 ||
(e.keyCode >= 35 && e.keyCode <= 39)) {
// let it happen, don't do anything
return;
}
else {
event.preventDefault();
}
// Ensure that it is a number and stop the keypress
if ($(this).val().length <= 2 || (e.shiftKey || (e.keyCode < 48 || e.keyCode > 57)) && (e.keyCode < 96 || e.keyCode > 105)) {
e.preventDefault();
}
else {
event.preventDefault();
}
});
}); // end of $

ASCII key codes
Minus symbol ASCII value is 45
$("#Age").keydown(function (e) {
if (e.keyCode != 45) { //it does't allow user to enter minus(-) symbol
..
}
else {
event.preventDefault();
}
}); // end of $

javascript : key validation

im using javascript to validate keys in textbox. it is not working :(
function numeric(e) {
return ((e.keyCode == 8) ||
(e.keyCode == 9) ||
(e.keyCode > 47 && e.keyCode < 58) ||
(e.keyCode > 36 && e.keyCode < 41) ||
(e.keyCode == 46) ||
(e.keyCode > 95 && e.keyCode < 106) ||
e.keyCode == 190 ||
e.keyCode == 110);
}
help me...

function numeric(e) {
e = e || window.event;
keycode = e.keyCode || e.which;
if(keycode === 13){
alert("cheese");
}
}

I know that in I.E. you can set event.keyCode=0 to suppress the key appearing in the control. But I think you need to trap the onkeydown. Firefox might have an equivalent. This is good because it prevents the key actually "arriving" at the control.
Also keep in mind that you might need to handle combinations of Shift + key and alt + key.
a good debug technique for this sort of thing is to say windows.status = event.keyCode,
and you can see what the keycode is as you type it...

Just try out the following code. I have checked F5 keycode, you can check as you want
function disableKey(event)
{
if (!event) event = window.event;
if (!event) return;
var keyCode = event.keyCode ? event.keyCode : event.charCode;
if (keyCode == 116) {
showMsg("This functionality is disabled.");
window.status = "F5 key detected! Attempting to disabling default response.";
window.setTimeout("window.status='';", 2000);
// Standard DOM (Mozilla):
if (event.preventDefault) event.preventDefault();
//IE (exclude Opera with !event.preventDefault):
if (document.all && event && !event.preventDefault) {
event.cancelBubble = true;
event.returnValue = false;
event.keyCode = 0;
}
return false;
}
}
function setEventListenerForFrame(eventListener)
{
document.getElementById('your_textbox').onkeydown = eventListener;
//frames['frame'].document.onkeypress = eventListener;
}
<body onload="setEventListener(disableKey);">

Try this if you want a numbers only textbox:
function numbercheck(event) {
var unicode = event.charCode; var unicode1 = event.keyCode; if (navigator.userAgent.indexOf("Firefox") != -1 || navigator.userAgent.indexOf("Safari") != -1) {
if (unicode1 != 8) {
if ((unicode >= 48 && unicode <= 57) || unicode1 == 37 || unicode1 == 39 || unicode1 == 35 || unicode1 == 36 || unicode1 == 9 || unicode1 == 46)
{ return true; }
else
{ return false; }
}
}
if (navigator.userAgent.indexOf("MSIE") != -1 || navigator.userAgent.indexOf("Opera") == -1) {
if (unicode1 != 8) {
if (unicode1 >= 48 && unicode1 <= 57)
{ return true; }
else
{ return false; }
}
}
}
And in your textbox call it on the onkeypress event:
onkeypress="return numbercheck(event)"