why is the message "wrong username password" not staying on page - javascript

I have the following page with a javascript file, when the user enters the wrong username/password the message "wrong username password" is output to page; however, the message does not stay on the page. For some reason the page gets refresh.
<html>
<head>
<script src="letmein.js"></script>
</head>
<body>
<h1 id="h1">JavaScript Test Page</h1>
<p id="p">Click the link to login into the application</p>
<p>login</p>
<form id="myForm" name="myForm" onSubmit="letmein();">
<p>username:
<input type="text" name="username">
</p>
<p>password:
<input type="text" name="password">
</p>
<input type="submit" value="Login">
</form>
<p id="hidden"></p>
clear
</body>
</html>
javascript file
var username = "admin";
var password = "letmein";
var counter = 0;
//login form authentication
function letmein() {
var formUser = document.forms['myForm']['username'].value;
var formPass = document.forms['myForm']['password'].value;
if(formUser === username && formPass === password) {
window.open("file:///home/jorge/usersearch.html");
}
counter++;
document.getElementById("hidden").innerHTML = "Wrong username or password!"
if(counter === 3) {
alert("Access Denied!");
}
}
//close window
function closeWindow() {
close();
};

I think clicking the button submits the form. You need to return false on onSubmit in order to avoid submitting the form.
<html>
<head>
<script src="letmein.js"></script>
</head>
<body>
<h1 id="h1">JavaScript Test Page</h1>
<p id="p">Click the link to login into the application</p>
<p>login</p>
<form id="myForm" name="myForm" onSubmit="letmein(); return false;">
<p>username:
<input type="text" name="username">
</p>
<p>password:
<input type="text" name="password">
</p>
<input type="submit" value="Login">
</form>
<p id="hidden"></p>
clear
</body>
</html>

You need to stop the form's default action. For example:
function letmein(e) {
if(validationFails) {
e.preventDefault(); //this will stop the form from submitting
}
}

Related

How to redirect to dashboard if the login is correct

here validating login details. but how do i redirect to dashboard if login credentials are correct. And how do i avoid page refresh on submit with getting all the data from the form
if(db.email == logEmail.value && db.password == logPass.value){
window.location = '../html/dashboard';
}else{
console.log('username and password incorrect');
}
}
Since you did not post your entire form I would assume it goes something like this:
<!DOCTYPE html>
<html>
<head>
<script>
function sampleLogin() {
if (/* some condition false*/) {
alert("cannot Submit form");
window.location = ''; // your desired location
return false; //<-- return false you can redirect here if you want
}
}
</script>
</head>
<body>
<form action="someUrl" method="post" onsubmit="sampleLogin()">
User:
<input type="text" id="user" name="user">
<br>
<br> Pass:
<input type="password" id="password" name="password">
<br>
<br>
<button>Submit</button>
</form>
</body>
</html>
If your submit method returns false it does not redirect or submits and you can use this to perform your own logic of redirecting.

Javascript | Simple Form Validation Wont Work

I have been working on this really simple login, where all i want to do is say, if the password is "apple" and password is "123" then link me to another page when i click submit button.
I gave up on the submit button linking portion but i still don't understand why my code won't register, everything looks right to me
<!DOCTYPE html>
<html>
<body>
<form name="loginForm">
<input type="text" name="username" placeholder="Username" value=""/>
<input type="password" name="password" placeholder="Password" value=""/>
<input type="button" name="submit" value="Login" onclick="validate()" />
</form>
<script type="text/javascript">
function validate() {
var user = document.loginForm.username.value;
return user;
var pass = document.loginForm.password.value;
return pass;
if ( (user=="apple") && (pass=="123") ) {
document.write("It worked");
} else {
document.write("Wrong Password");
}
}
</script>
</body>
</html>
Suggestions:
return keyword will exit the function, so the code after return won't be reached. To remove the two 'return' statement is the first step.
document.write will clear the page after document is loaded. You probably need alert function
try using document.getElementById/getElementByName (which is better) instead of document.loginForm...
It is also better to put onsubmit in the form tag (fired after type=submit button is clicked) instead of onclick event for button.
It is better to put Javascript inside the HTML head tag.
Below is a much better/working version:
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
function validate() {
var user = document.getElementById("username").value;
var pass = document.getElementById("password").value;
if ( (user=="apple") && (pass=="123") ) {
alert("It worked");
return true;
} else {
alert("Wrong password");
return false;
}
}
</script>
</head>
<body>
<form action="" onsubmit='javascript:return validate()'>
<input type="text" id="username" placeholder="Username" value=""/>
<input type="password" id="password" placeholder="Password" value=""/>
<input type="submit" value="Login" />
</form>
</body>
</html>

More Simple Password System Stuff

Sorry guys, first time playing around with this. Here's the HTML:
<!DOCTYPE html>
<html>
<head>
<title>SuM BUTtonsS DOe</title>
<link rel="stylesheet" href="buttons.css"/>
</head>
<body>
<p>Please enter the password</p>
<form id="enter" onSubmit="javascript:passCheck()">
<input id="password" type="password" placeholder="Password">
</form>
<p id="incorrect"><em>INCORRECT PASSWORD</em></p>
<script type="text/javascript">
function passCheck() {
var input = document.getElementById('password').value;
if (input == 'herro') {
window.alert("IT WORKS!!");
}
else {
var incorrect = document.getElementById('incorrect');
incorrect.style.display = "block";
}
}
</script>
</body>
</html>
When I enter the wrong password, INCORRECT PASSWORD comes up, but only for a fraction of a second. Then it's gone again. No idea why.
UPDATE:
<!DOCTYPE html>
<html>
<head>
<title>SuM BUTtonsS DOe</title>
<link rel="stylesheet" href="buttons.css"/>
</head>
<body>
<p>Please enter the password</p>
<form id="enter" onSubmit="javascript:passCheck()">
<input id="password" type="password" placeholder="Password">
</form>
<p id="incorrect"><em>INCORRECT PASSWORD</em></p>
<script type="text/javascript">
function passCheck() {
var input = document.getElementById('password').value;
if (input == 'herro') {
window.alert("IT WORKS!!");
}
else {
var incorrect = document.getElementById('incorrect');
incorrect.style.display = "block";
return false;
}
}
</script>
</body>
</html>
On submit, the form will trigger the default action, which in this case is to submit the contents to the same page (for lack of an action property).
So what you're seeing is the JavaScript runs and changes the style to show the error message, then the page reloads.
To ensure the page doesn't reload put return false at the end of passCheck. Better would be to use addEventListener and event.preventDefault(), but that's a little bit more involved.
<p>Please enter the password</p>
<form id="enter" onSubmit="passCheck(); return false;">
<input id="password" type="password" placeholder="Password">
<input type="submit" value="Submit"/>
</form>
<p id="incorrect" style="display: none"><em>INCORRECT PASSWORD</em></p>
<script type="text/javascript">
function passCheck() {
var input = document.getElementById('password').value;
if (input == 'herro') {
window.alert("IT WORKS!!");
}
else {
var incorrect = document.getElementById('incorrect');
incorrect.style.display = "block";
}
}
</script>

js validation of not null field

I have done a login page. I want my js validateForm()function to alert a user if they have left out the username or password. This is the code I have got at the moment.
<!DOCTYPE html>
<html>
<head>
<script>
function validateForm()
{
var x=document.forms["myForm"]["username"].value;
if (x==null || x=="")
{
alert("Please enter username");
return false;
}
}
</script>
</head>
<div class="users form">
<br>
<form name="myform" action="Employees/login" onsubmit="return validateForm()" method="post" >
<?php
if (isset($error)) {
echo "<p style='color:red;font-size: 20px''>Username or Password is invalid. Please try again.</p>";
}?>
<p>Enter Username:
<input type="text" name="username" placeholder="username" style="height: 25px;width: 160px;"/></p>
<br><br>
<p>Enter Password:
<input type="password" name="password" placeholder="password" style="height: 25px;width: 160px;"/></p>
<br>
<input type="submit" style="height:35px;width:100px;font-size: 18px; align:center;" value="Sign in">
</form>
</div>
At the moment it is not working, and I think the problem is with the code line "var x=document.forms["myForm"]["username"].value;" Can someone please help?
The issue is forms["myForm"], you used an uppercase F, when actually your form name is all lowercase so it should be:
var x=document.forms["myform"]["username"].value;
// ^ lowercase
Not part of the problem, but you might prefer to use unobtrusive JavaScript to set the onsubmit handler instead of in the HTML attribute:
window.onload = function(){
document.forms["myform"].onsubmit = validateForm;
};
Now, in validateForm you can use this instead of finding the form manually.
function validateForm()
{
var x = this["username"].value;
...
}

How to adapt current code to run without using a form?

How would I adapt this code to run without using the form, but the prompt() method instead? By including a prompt instead of a form to ask for user input.
<html>
<head>
<title>Login page</title>
</head>
<body>
<h1 style="font-family:Comic Sans Ms;text-align="center";font-size:20pt; color:#00FF00;>Simple Login Page</h1>
<form name="login">
Username<input type="text" name="userid"/>
Password<input type="password" name="pswrd"/>
<input type="button" onclick="check(this.form)" value="Login"/>
<input type="reset" value="Cancel"/>
</form>
<script language="javascript">
function check(form)/*function to check userid & password*/ {
/*the following code checkes whether the entered userid and password are matching*/
if(form.userid.value == "myuserid" && form.pswrd.value == "mypswrd") {
window.open('target.html')/*opens the target page while Id & password matches*/
}
else {
alert("Error Password or Username")/*displays error message*/
}
}
</script>
</body>
</html>
Thanks!

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