Develop Reference

How to make an HTML element readonly based on PHP value

I have this code:
<input type = "text" value = "$va" name = "n"/>
and I want it to be readonly if va is not whitespace. How can I accomplish this?

This should make it so that if $va contains whitespace the field will be readonly.
<?php
$readonly = (!empty($va) && strlen(trim($va)) == 0) ? null : 'readonly';
echo '<input type="text" value="'.$va.'" name = "n" '.$readonly.' />';
However I'm not sure if you also want to include an empty string as "only including whitespace", in which case you could alter the first line to:
$readonly = (strlen(trim($va)) == 0) ? null : 'readonly';

1st Option With Java Script
in javascript you can do it like this:
1st: put an id to your element
<input type = "text" value = "$va" name = "n" id='n'/> //i just made it the same as the name
2nd: get the element with the id of 'n'
<script>
$(document).ready(function(){
var nValue = $("#n").val();
if( nValue != " " ) {
$("#n").prop("readonly",true);
}
});
</script>
2nd Option With PHP
in php, assuming that you are printing your element via php:
//other codes here
<?php $va = "noAWhiteSpace";
$readOnly = "";
if($va != ""){
$readOnly = "readonly";
}
?>
<input type = "text" value = "<?php echo $va; ?>" name = "n" <?php echo $readOnly; ?> />;

here is
<input type = "text" value = "$va" name = "n" <?= ($va != '' || $va == null) ? '' : 'readonly'; ?>/>
check https://www.php.net/manual/en/control-structures.if.php

Hide zero values of an empty input(number type)

I have a form that gives me data from database, i have number input type. By default it is "0" showed for empty entries. I want to hide "0" from the field and show the value just if is different of 0.
I tried with the code below but it doesn't work.
<input data-validate="number" value="<?php echo $value; ?>" class="form-control" onload="if(this.value == '0') { this.value = ' '; } " >

Add ternary operator to PHP block instead:
<input data-validate="number" value="<?php echo ($value != '0' ? $value : ''); ?>" class="form-control">

I wrote a minimal php function to do this
function fnB($input){
//function to make values blank in number input boxes
if ($input==0) $r="";
else $r=$input;
return $r;}
?>
So in the form one can then enter
value = <?php echo fnB($value);?>

get radio button value (PhP MySQL and ajax)

Newbie here..
I have this code for my displaying the database records in a table,
I want to know how do i get the value of radio button (the radio button contains the id of selected row). I tried doing it in javascript but no luck.
table.php
<table border="1">
<th></th>
<th>Particulars</th>
<th>Amount</th>
<?php
include('includes/config.php');
$qry = $con->prepare('SELECT * FROM fees');
$qry->execute();
$row = $qry->rowCount();
while ($row = $qry->fetch(PDO::FETCH_ASSOC)) {
$id = $row['fee_id'];
$fee = $row['fee_name'];
$amt = $row['amount'];
?>
<?php echo "
<tr title='Click to edit or delete record'>
<td><input type = 'radio' name = 'radio' class ='radio' value = $row[fee_id]></td>
<td>$fee</td>
<td>$amt</td>
</tr>
"; ?>
<?php } ?>
</table>
<input type="button" value="Delete Selected Fee" style="width:250px; height:40px;font-weight:bold;" onclick="delete();"><br><br>
javascript code
<script type="text/javascript">
function delete(){
if (document.getElementsByClassName(this.class).checked){
var val = document.getElementsByClassName(this.class).value;
alert (val);
}
}
</script>

Use this
function delete(){
if($('input[name="radio"]').is(':checked')){
var val = $('input[name="radio"]').val();
console.log(val);
}
}

I suggest you to use hidden field instead if you don't want to show. The property of radio buttons is to show only true / false value. It may be on / off or yes / no, according to your uses. Use like
<input type = 'hidden' name = 'whatever' class ='radio' value =<?php echo $row['fee_id']; ?>>

You can try this, this should get your radio button value using your input name.
<script type="text/javascript">
function delete(){
if($('input[name="radio"]').is(':checked')){
var val = $('input[name="radio"]').val();
alert (val);
}
}
</script>

Following code will give you your radio button value
<script type="text/javascript">
function delete(){
if($('input[name="radio"]').is(':checked')){
var val = $('input[name="radio"]').val();
alert (val);
}
}
</script>
you can use console.log(val);

copy text from one textbox to another based on a condition

I am working on javascript.
Consider two textboxes tb1 and tb2 respectively
The value present in tb1 should be copied in tb2 based on a condition. If the condition is true nothing needs to be copied. If the condition is false the value in tb1 should also be initialised to tb2. Is it possible..

<!DOCTYPE HTML>
<html>
<head>
</head>
<body>
<div>
<span>tb1:</span>
<input id="tb1" type="text" value="TextBox Value 1"/>
</div>
<div>
<span>tb2:</span>
<input id="tb2" type="text" value="TextBox Value 2"/>
</div>
<input type="button" onclick="exchange()" value="Exchange">
<script type="text/javascript">
function exchange(){
var tb1 = document.getElementById('tb1');
var tb2 = document.getElementById('tb2');
var condition = function(){
return true;
};
if(condition()){
var buf = tb1.value;
tb1.value = tb2.value;
tb2.value = buf;
}
}
</script>
</body>
</html>

Here's a function that can do what you need:
function compareAndCopy() {
var tb1 = document.getElementById("tb1");
var tb2 = document.getElementById("tb2");
if (tb1.value == "hey") {
tb2.value = tb1.value;
} else {
alert("No match");
}
}
//Add a handler
document.getElementById("tb1").onblur = compareAndCopy;
It is currently checking if tb1 equals hey on blur.
Working demo: http://jsfiddle.net/4L5pE/

yes, this is possible. You need to define when you want it to happen. onkeypress, or onblur of first text box you can call a function that validates your condition and then copies the values.
tb1.onblur(function(){ if(condition) tb2.value = tb1.value }
the code above will not work, its just a pseudo.

Unable to check if a javascript checkbox array element is checked or not?

What is want is - when the checkbox is checked option no. 5 in select list will be selected and when the checkbox is unchecked option no. 0 will be selected in the select list.
The select list and the checkboxes are generated dynamically in the php code as below :
echo "<select name='coupons".$i."' id='coupons".$i."'>";
------- All Options --------
echo "</select>";
<input type='checkbox' name='myCheckbox[]' value='<?php echo $i."_".$row->id; ?>' onclick='setCCode("myCheckbox[]",<?php echo $i;?>)'>
-----------------------------------------------------------------------------
Solved the second requirement on my own now ..... thanks to all for your inputs
just added the following line in the checkAll() within the for loop
setCCode(children[i],i+1);
The javascript function :
function setCCode(checkbox_name,i)
{
var form_object = document.getElementsByName(checkbox_name+"["+i+"]");
var selname = document.getElementsByName("coupons"+i)[0];
if(form_object.checked) {
selname.selectedIndex = 5;
}
else {
selname.selectedIndex = 0;
}
}
The above issue is solved....... thanks to all
Now what i need to do is when a user checks a checkbox to select or deselect all the dynamically generated checkboxes on the form the above logic should work.
<input type='checkbox' name='checkall' onChange="checkAll(this, 'myCheckbox[]')">
<span class="chkall">Check / Uncheck All</span>
<input type='checkbox' name='myCheckbox[]' value='<?php echo $i."_".$row->id; ?>' onclick='setCCode(this,<?php echo $i;?>)'>
The javascript code i am using to select/deselect all checkboxes on form is as below :
function checkAll(parent, field)
{
var children = document.getElementsByName(field);
var newValue = parent.checked;
for (i = 0; i < children.length; i++){
if (children[i].disabled == false) {
children[i].checked = newValue;
}
}
}
function setCCode(Sender,i)
{
document.getElementsByName("coupons"+i)[0].selectedIndex = Sender.checked ? 5 : 0;
}

getElementsByName returns an array of objects. Replace the line with:
var form_object = document.getElementsByName(checkbox_name+"["+i+"]")[0];

You can pass refference to the checkbox itself as a parameter
<input type='checkbox' name='myCheckbox[]' value='<?php echo $i."_".$row->id; ?>' onclick='setCCode(this,<?php echo $i;?>)'>
function setCCode(Sender,i)
{
document.getElementsByName("coupons"+i)[0].selectedIndex = Sender.checked ? 5 : 0;
}

If you have a reference to the form that the checkbox is in, and it has a unique name in the form, then you can access it as:
form_object = form.elements[ checkbox_name + "[" + i + "]" ];
and you can also use the ternary operator to make the code more concise:
selname.selectedIndex = form_object.checked? 5 : 0;
Edit
Sorry, missed the obvious. If you pass a refereference to the checkbox in the handler, then you can also get the form (all form controls have a form property that references the form they are in). So as Jan Pfeifer suggested (abbreviated markup):
<input ... onclick='setCCode(this, <?php echo $i;?>)'>
then the script is just:
function setCCode(checkbox, i)
{
checkbox.form.elements['coupons' + i].selectedIndex = checkbox.checked? 5 : 0;
}