javascript function not working with my html form - javascript

i have an html code for a form and a javascript function that will perform age calculation and populate it in the next page but the calculation is not working. every other field in the form in being displayed in the next page but the calculation is not just working.
<!DOCTYPE html>
<html>
<body>
<script src="text/javascript">
function calculate_age(birth_month,birth_day,birth_year)
{
var today_date = new Date();
var today_year = today_date.getFullYear();
var today_month = today_date.getMonth();
today_day = today_date.getDate();
age = today_year - birth_year;
if ( today_month < (birth_month - 1))
{
age--;
}
if (((birth_month - 1) == today_month) && (today_day < birth_day))
{
age--;
}
return age--;
document.getElementById("myForm").innerHTML = window.calculate_age()
}
</script>
<form action="new1.php" method="post" id="myForm">
First name:<br>
<input type="text" name="firstname">
<br>
Last name:<br>
<input type="text" name="lastname">
<br>
Date of Birth:<br>
<input type="date" name="age" id="dob" script="calculate_age">
<br><br>
<input type="submit" onclick="calculate_age(birth_month,birth_day,birth_year)" value="Submit">
</form>
</body>
</html>

return age--;
document.getElementById("myForm").innerHTML = window.calculate_age()
The statement that makes modification to your DOM element is never reached.

the first answer is absolutely right. additionally, your button's type is "submit". so, when you click that button, first it runs the function, then posts the page, and all your values are lost because the function that calculates age doesn't run after the form is submitted. you have to change the button's type or run the function on window onload. besides, the function that calculates age have compilation errors. the part that changes the innerhtml of the form needs ";" at the end

Related

How to print output of players names using JS & HTML

Hey so I am new to using JS and HTML and still practicing the language, I am trying to print out the user name of both players but without using alert. I want to print the player's names and later going to change it up using CSS but having trouble with the simplest way of printing user inputs I have this so far and was wondering why it is not working, any help will be appreciated.
function welcome(){
var first = document.getElementById("FirstName").value;
var last = document.getElementById("LastName").value;
var Print_name = "Welcome " + first +" "+ last;
console.log(Print_name);
}
<!DOCTYPE html>
<html>
<head>
<title>Print Names</title>
</head>
<body>
<form method="get">
<label for="Player1Name">Player 1 Name:</label>
<input type="text" id="Player1Name" name="player1Name" placeholder="Name"><br>
<label for="Player2Name">Player 2 Name:</label>
<input type="text" id="Player2Name" name="player2Name" placeholder="Name"><br>
<input type="submit" value="Submit" class="btn">
</form>
<script>
/*javascript code here*/
</script>
</body>
</html>
You should find an HTML element (with id="Player1Name") and (with id="Player2Name").
Try it code in HTML
<input type="submit" value="Submit" class="btn" onclick="welcome()">
Try it code in JavaScript
function welcome(){
var first = document.getElementById("Player1Name").value;
var last = document.getElementById("Player2Name").value;
var Print_name = "Welcome " + first +" "+ last;
alert(Print_name);
}
your document.getElementById is referencing the wrong Id.
So if you text field is defined as
<input type="text" **id="Player1Name"** name="player1Name" placeholder="Name">
Then what you should be doing is document.getElementById("Player1Name").value
The same goes with the Player2Name field.

How to verify the elements of a form in Javascript then Move to a PHP page?

I want to verify the inputs by javascrpit function perform() and move to a php page named i.php to save the datas in the databasse.
Here is the code:
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<form action="i.php" method="post">
<br>
Name <input type="text" name="name" id="name" >
<span id="err"></span>
</br>
<br>
Password <input type="Password" name="Password" id="password">
<span id="perr"></span>
</br>
<br>
Gender
<input type="radio" name="gender" id="gender" value="male">Male
<input type="radio" name="gender" id="gender" value="female">Female
</br>
<br>
Department <select name="department" id="department">
<option>------</option>
<option>ECE</option>
<option>BBA</option>
<option>ENG</option>
</select>
</br>
<br>
<button name="btn" type="button" id="btn" onclick="perform()" >Button</button>
<input type="submit" name="submit" value="Submit">
<input type="reset" name="reset" value="Clear">
</br>
</form>
<script type="text/javascript">
function perform()
{
var name = document.getElementById('name').value;
var pass = document.getElementById('password').value;
var dept = document.getElementById('department').value;
var gender = document.getElementsByName('gender');
var r =3;
if (name.length==0)
{
document.getElementById('err').innerHTML = "name not found";
r++;
}
if (pass.length<=6 || pass.length>=32 )
{
document.getElementById('perr').innerHTML = "password error";
r++;
}
if(r==3)
{
window.location= "i.php";
}
}
</script>
</body>
</html>*
In i.php page i used var_dump to see the datas whether it has been submitted or not. code of the i.php page:
<!Doctype html>
<html>
<head></head>
<body>
<?php
var_dump($_POST);
?>
</body>
</html>
But its showing arry(0) {}
looks like there nothing that has been submitted.
The issue is that you're redirecting with javascript, and losing the entire form and it's data by doing so.
When the form is valid, submit it rather than redirecting
function perform() {
var _name = document.getElementById('name').value;
var pass = document.getElementById('password').value;
var dept = document.getElementById('department').value;
var gender = document.getElementsByName('gender');
var valid = true;
if (_name.length === 0) {
document.getElementById('err').innerHTML = "name not found";
valid = false;
}
if (pass.length <= 6 || pass.length >= 32) {
document.getElementById('perr').innerHTML = "password error";
valid = false;
}
if (valid) {
document.querySelector('form').submit();
}
}
Note that name is not a good name for variables or form elements, as it already exists in window.name, and that a submit button can not be named submit as it overwrites the named form.submit() function
Another option would be to just remove all the javascript, and use HTML5 validation instead.
Use this code:
<form action="i.php" method="post" onsubmit="perform();">
And in javascript make these changes:
if(r!=3) {
alert('please complete the form';
return false;
}
Javascript doesn't send POST headers with window.location!
By using this code, you don't need to use a button, javascript perform() function runs when the submit button is clicked in the form.
If form values are entered truly, javascript perform() does not return and form submits; else, the function returns and prevents submitting the form.
The problem is you are not submitting the form you are just going to a different page with javascript without passing along any variables. so instead of doing
window.location= "i.php";
you should submit the form like so
document.getElementById("formId").submit();
so you should give the form the id formId
The problem is that you are merely redirecting to the i.php page without posting any data. Replace this line in your JS:
window.location = "i.php";
with this
document.getElementsByTagName('form')[0].submit();
This will find the form in your DOM and submit it along with the data that has been input, preserving the values for your action page.
You also need to rename your submit-button for this to work. Otherwise you will not be able to call the submit function on the form programmatically.
<input type="submit" name="submit-btn" value="Submit" />
should do the trick. However, I don't really see the point of the submit button in addition to your validation/submission button.
Full code sample of the solution here: https://jsfiddle.net/dwu96jqw/1/
by press btn you redirect only and your form dont submitted for transfer via _POST
you should change your code :
<form action="i.php" method="post" id ="form1">
and :
if(r==3)
{
form1.submit();
}
window.location will redirect you to the page, to preserve field values return it
if(r==3)
{
return true;
}

how to dynamically insert character in middle input text with JS

I have an input text box to fill in with hours from 00:00 to 23:59
I'd like to dynamically insert the double point ":" after the 2 first characters, something like in http://www.railtime.be/website/home-fr which is even giving an error message when wrong hours are given like 30:66... I can't figure out how it has been done, any idea?
<input type="text" name="time" id="time" placeholder="00:00" maxlength="5" value="">
I think a keypress function has been used but what with?
Thanks in advance!
Resolved with dfsq solution:
$('input#time').on('keyup', function(e) {
if (e.which && this.value.length === 2 && e.which !== 8) {
this.value += ':';
}
});
<input type="time"> isn't supported in Firefox etc.
If you wish to avoid jQuery, just use this simple code wherein your ':' would be inserted at the time of typing itself using the keyup event-
<html>
<head>
<script type="text/javascript">
function insertColon(e){
var unicode=e.keyCode? e.keyCode : e.charCode
if(unicode!=8){// this avoids backspace to spoil your logic
var textval=document.getElementById("time").value;
if(textval.length==3&&textval.charAt(1)!=":"&&textval.charAt(2)!=":"){// this case arises when backspace is used
textval=textval.substring(0,2)+":"+textval.substring(2,3);
document.getElementById("time").value=textval;
}
else if(textval.length==2&&textval.charAt(1)!=":"){// normal case
textval=textval+":";
document.getElementById("time").value=textval;
}
}
else if(unicode==46&&textval.length>=3&&textval.charAt(1)!=":"&&textval.charAt(2)!=":"){
textval=textval.substring(0,2)+":"+textval.substring(2);`document.getElementById("time").value=textval;`
}
}
</script>
</head>
<body>
<input type="text" name="time" id="time" placeholder="00:00" maxlength="5" value="" onKeyup="insertColon(event);">
</body>
</html>
You can yourself add some little code to script to check if the ranges of hours and minutes are falling within range.
This may help you out. http://jsfiddle.net/e2DzT/380/
It checks for the correct format, and if it is empty. It will output the correct response. Format can be only in 15:30 format.
When the correct format is found, the form is submitted.
<form id="login" name="login" method="post" action="#">
Just change it to what you want it to do.
You can try the following Javascript code:
function appendColon(){
var time=document.getElementById("time").value;
var hours=time.substring(0, 2);
var minutes=time.substring(2, 4);
document.getElementById("time").value=hours+":"+minutes;
}
<input type="text" name="time" id="time" onchange="appendColon()" placeholder="00:00" maxlength="5" value="">
In the onchange event of the input, appends : between hours and minutes.

Why is a HTML form field showing the calculations in the output field

I've created a basic profit calculator which is pretty much working fine. My issue is that every time I enter a number into each of the relevant fields, you can see the workings out in the "Total profit" field. It first tells me my entry is NaN, then -infinity, and then shows the workings. Once I click on my calculate button, I am then finally displayed with the correct number.
For this post I am not concerned with why it is producing the NaN (not a number), but why am I seeing it populated in the field in the first place. I want this field to remain blank until I click Calculate, and then see the resulting number. I suspect it's to do with my JavaScript code but I am a complete newbie - and very stuck.
Your thoughts are most appreciative.
<form id="profitCalculator" action="" class="dark-matter">
<h1>Profit Calculator</h1>
<fieldset>
<p><label>Case Cost:<br />£
<input name="casecost" type="text" value="" size="14" maxlength="8" /></label></p>
<p><label>Units per case:<br /> <input name="packs" type="text" value="1" size="14" maxlength="8" /></label></p>
<p><label>Sell price:<br /> £ <input name="sell_price" type="text" value="" size="14" maxlength="8" /></label></p>
<p><input type="button" class="button" OnClick="Circle_calc(this.form);" value="Calculate"></p>
<p>Total Profit:<br /> £ <input name="profit" type="text" value="0" autocomplete="off" SIZE=14></p>
<p><input type="reset" class="button" value="Reset"></p>
</fieldset>
</form>
And the JavaScript
<script type="text/javascript">
document.getElementById('profitCalculator').onclick = function () {
var casecost = this.elements['casecost'].value || 0;
var packs = this.elements['packs'].value || 0;
var sell_price = this.elements['sell_price'].value || 0;
var profit = (sell_price - casecost) / packs;
this.elements['profit'].value = profit.toFixed(2);
}
</script>
Thank you
You've set a click handler on the form element. Since click events bubble, clicks on the elements inside the form bubble to the form as well. So that's triggering an update to your profit element on anything that any element considers a click.
This diagram from the DOM3 events spec (which has since been folded into the DOM4 spec's events section) may help clarify how bubbling works:
You have a Onclick event on your button that calls Circle_calc function.
Change your function passing the form element as a parameter, and it will work.
Circle_calc = function (form) {
var casecost = form.elements['casecost'].value || 0;
var packs = form.elements['packs'].value || 0;
var sell_price = form.elements['sell_price'].value || 0;
var profit = (sell_price - casecost) / packs;
form.elements['profit'].value = profit.toFixed(2);
}
JsFiddle here

I can't post to google?

Here is the code for a small program where you put the keyword, choosing the search engine and then pressing "Search" button to search. But google don't leave me to POST. What else I can do?
EDIT: Yahoo and Bing works fine.
ERROR
405. That’s an error.
The request method POST is inappropriate for the URL
/search?q=computer. That’s all we know.
HTML
<form name="search" action="" method="Post" onSubmit="redirect()">
<input type="text" name="keyword"><br />
Google<input type="radio" name="ch" checked>
Yahoo!<input type="radio" name="ch">
Bing<input type="radio" name="ch"><br />
<input type="submit" value="Search">
</form>
Javascript
<script type="text/javascript">
var searchengine=[
"http://google.com/search?q=",
"http://search.yahoo.com/search?p=",
"http://bing.com/search?q="
];
function redirect()
{
var radioButtons = document.getElementsByName("ch");
for (var x = 0; x < radioButtons.length; x++) {
if (radioButtons[x].checked)
{
document.search.action = searchengine[x] + document.search.keyword.value;
}
}
}
</script>
But google don't leave me to POST. What else I can do?
Use GET rather than POST in your form, or just assign the relevant URL to window.location.
Here's an example of the latter. Some other changes:
Added some labels.
Changed how you're matching up the selected radio button and the searchengine to make it more robust/maintainable.
Changed the name of the search form. Since this gets dumped on the window object I avoid simple words like "search".
Properly encoded the keyword (you must encode URI parameters).
Live copy | Live source
HTML:
<form name="searchForm" action="" method="GET" onSubmit="return doSearch()">
<input type="text" name="keyword">
<br>
<label>Google<input type="radio" name="ch" value="google" checked></label>
<label>Yahoo!<input type="radio" name="ch" value="yahoo"></label>
<label>Bing<input type="radio" name="ch" value="bing"></label>
<br>
<input type="submit" value="Search">
</form>
JavaScript:
var searchengine = {
"google": "http://google.com/search?q=",
"yahoo": "http://search.yahoo.com/search?p=",
"bing": "http://bing.com/search?q="
};
function doSearch() {
var frm, index, cb;
frm = document.searchForm;
if (frm && frm.ch) {
if (frm.ch) {
for (index = 0; index < frm.ch.length; ++index) {
cb = frm.ch[index];
if (cb.checked) {
window.location = searchengine[cb.value] +
encodeURIComponent(frm.keyword.value);
}
}
}
}
return false; // Cancels form submission
}
"http:google.com/search?q=", is not formatted properly..
try "http://google.com/search?q="

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