Develop Reference

How can I validate user input (characters and number) with javascript?

From this example
I tried to validate user input when a button was clicked.
$("#check_data").click(function () {
var $userInput = $('#user_input'); //from HTML input box id="user_input"
var pattern = " /*My user input always be like "AB1234567"*/ ";
if ($userInput.val() == '' || !pattern.test($userInput.val())) {
alert('Please enter a valid code.');
return false;
}
});
My user input input always be like "AB1234567" with this exact same characters but different 7 digits number.
I'm new to Javascript and Jquery, if you have any better way to validate user input, please suggest it.
Thank you.

You can use below regex Expression to check
/[A-Za-z0-9]/g
Your code could be like this
var _pattern=/[A-Za-z0-9]/g
if($userInput.val().match(_pattern))
{
//your code goes here..
}
Thanks

You can use the below pattern to check
/^AB\d{7}$/
You can change code to
var pattern = '/^AB\d{7}$/';
if ($userInput.val() == '' || !pattern.test($userInput.val()))
{
alert('Please enter a valid code.');
return false;
}
\d{7} matches 7 digits in the range [0-9]

You can follow below code for this:
if ($userInput.val().match(/[^a-zA-Z0-9 ]/g))
{
// it is a valid value.
} else {
// show error here
}
Hope it helps you.

Try this one.
$("#check_data").click(function(){
var $userInput = $('#user_input').val();
var pattern = /^AB[0-9]{7}?/g;
if(!$userInput.match(pattern)){
alert('Please enter a valid code.');
return false;
}
});

Stop form whitespace when user pressing submit

Okay, so I have a form. Applied a function to it.
All I want to do is when the form is submitted it launches the function, it checks to see if there is white space and throws out a message. I have the following:
function empty() {
var x;
x = document.getElementById("Username").value;
if (x == "") {
alert("Please ensure you fill in the form correctly.");
};
}
<input type='submit' value='Register' onClick='return empty()' />
<input type='text' id="Username" />
This is fine for if someone pressed the space-bar once and enters one line of whitespace, but how do I edit the function so that no matter how many spaces of whitespace are entered with the space-bar it will always throw back the alert.
Thanks in advance. I am very new to JavaScript. So please be gentle.

Trim the string before testing it.
x = document.getElementById("Username").value.trim();
This will remove any whitespace at the beginning and end of the value.

I have made a function for the same, i added another checks (including a regular expresion to detect multiples empty spaces). So here is the code:
function checkEmpty(field){
if (field == "" ||
field == null ||
field == "undefinied"){
return false;
}
else if(/^\s*$/.test(field)){
return false;
}
else{
return true;
}
}
Here is an example working with jquery: https://jsfiddle.net/p87qeL7f/
Here is the example in pure javascript: https://jsfiddle.net/g7oxmhon/
Note: the function checkEmpty still be the same for both

this work for me
$(document).ready(function() {
$('#Description').bind('input', function() {
var c = this.selectionStart,
r = /[^a-z0-9 .]/gi,
v = $(this).val();
if (r.test(v)) {
$(this).val(v.replace(r, ''));
c--;
}
this.setSelectionRange(c, c);
});
});
function checkEmpty(field) { //1Apr2022 new code
if (field == "" ||
field == null ||
field == "undefinied") {
return false;
} else if (/^\s*$/.test(field)) {
return false;
} else {
return true;
}
}

Form submits with passwords not matching (JavaScript)

The code I have been working on incorrectly allows the form to submit when password1 and password2 do not match. I'm stumped. Any help would be greatly appreciated. I've been using this site as a reference to learn coding. The community here is outstanding. Thanks in advance.
if ($.trim(Appery("register_firstname").val()) != "") {
if ($.trim(Appery("register_lastname").val()) != "") {
if (Appery("register_password1").val() == Appery("register_password2").val()) {
if ($.trim(Appery("register_email").val()) != "") {
if (!document.getElementsByName("register_email")[0].checkValidity || document.getElementsByName("register_email")[0].checkValidity()) {
if ($.trim(Appery("register_password1").val()) != "") {
{signupService.execute({});
}
else {
document.getElementById("registrationpassword_error").innerHTML = "Please enter a password."; {
document.getElementById("register_password1").focus();
}
}
}else {
document.getElementById("registrationemail_error").innerHTML = "Email Address not valid.";
{
document.getElementById("register_email").focus();
}
}
} else {
document.getElementById("registrationemail_error").innerHTML = "Please enter your email."; {
document.getElementById("register_email").focus();
}
}
} else {
document.getElementById("registrationpassword_error").innerHTML = "Passwords do not match."; {
document.getElementById("register_password1").focus();
}
}
} else {
document.getElementById("registrationlastname_error").innerHTML = "Please enter your last name."; {
document.getElementById("register_lastname").focus();
}
//alert("Please enter your last name.");
}
} else {
document.getElementById("registrationfirstname_error").innerHTML = "Please enter your first name."; {
document.getElementById("register_firstname").focus();
}
}
}

You have too many conditional checks in series, and your missing the '}' braces to close out all of the 'if' conditions your wrote. The number of left braces and right braces should match.I would separate your 'if' conditions so that password validation is DONE before validating other inputs. Each 'if' condition should have a 'true' / 'false' output that can be checked at the end of your code to see if all conditions are 'true'. That is how I do my validation. Each conditional check is separate from the others.

I am unsure about what Appery is, but if it is a normal HTML or JSP page that you are working on then, the form will submit on click of the submit button irrespective of what the above code returns.
I assume you are using a normal button for submitting the form on click on which the above code will run and signupService.execute({}); submits the form.
Did try checking with alerts that whether the control actually goes inside the last if loop?

JavaScript form validation, check if string contains

I have some form validation on my website.
If the account code field contains "XXX" and the reference field is blank, I want an alert to come up for the user to populate the reference field.
I have read that indexOf is the function I need, but the code below does not appear to work. Any ideas?
<SCRIPT>
if (form.account.value.indexOf("XXX") != -1 & form.reference.value == "") {
alert("Please Enter Reference Number");
form.reference.focus( );
return false;
}
</script>

Can you try:
if (form.account.value.indexOf("XXX") != -1 && form.reference.value == "") {
alert("Please Enter Reference Number");
form.reference.focus( );
return false;
}
This corrects the AND clause, which uses && not &.

Javascript disable space key for change password textboxes

,Hi all,
var veri = {
YeniSifreTextBox: $('#YeniSifreTextBox_I').val(),
YeniSifreTekrarTextBox: $('#YeniSifreTekrarTextBox_I').val(),
};
if (veri.YeniSifreTextBox == '' || veri.YeniSifreTekrarTextBox == '') {
alert("Password Can not be empty!");
}
else if (veri.YeniSifreTextBox != veri.YeniSifreTekrarTextBox) {
alert("Passwords dont not match !");
}
I can control password can not be empty and passwords dont not match with above codes.
I want to disable to enter space key while user write password.
User must never use space in keyboard inside of 2 textboxes.
1.textbox YeniSifreTextBox_I
2.textbox YeniSifreTekrarTextBox_I

You can use the below javaScript code to block the space key,
function RestrictSpace() {
if (event.keyCode == 32) {
return false;
}
}
HTML
<textarea onkeypress="return RestrictSpace()"></textarea>
Hope this helps you.

<input type="number"
id="cardNumber"
name="cardNumber"
required
onKeyDown="if(event.keyCode === 32)
return false;">
You can implement the same functionality, without creating a custom function.