Send parameter to the PHP-function from JavaScript

Question

I've a such PHP-script:

<?php
 $menuItemList = getSubPkgCategForDDList(echo "<script>showSubCatForMenuItem();</script>");
 if(isset($menuItemList)){
 foreach($menuItemList as $u){
 ?>
 <p><span contenteditable="true"><?php echo $u->name ?></span><button type="button" class="btn btn-danger btn-xs" onclick="deleteCategory(<?php echo $u->pkg_cat_ddlist_id ?>)">Delete</button>
 <button type="button" class="btn btn-success btn-xs" onclick="editCategory(<?php echo $u->pkg_cat_ddlist_id ?>,<?php echo "'".$u->name."'" ?>)">Save</button></p>
 <?php
 }
 }
?>

Function getSubPkgCategForDDList must generate html-code,so it depends from parameter, which is send to this function. I get this parameter from such js-function showSubCatForMenuItem():

function showSubCatForMenuItem(){
 console.log($('#menuItem').val());
 return $('#menuItem').val();
 }

This function takes data from such dropdown list:

<select id="menuItem" onchange="showSubCatForMenuItem()">
 <?php
 $itemList = getPackCategoriesForAsideMenu();
 if(isset($itemList)){
 foreach($itemList as $u){
 ?>
 <option value="<?php echo $u->pkg_cat_ddlist_id ?>"><?php echo $u->name ?></option>
 <?php
 }
 }
 ?>
 </select>

How to do that parameter transfer is correctly, when I load page and select item from dropdown list? Sorry for my English.

• Mubin: you need to call ajax request on dropdown change to send variables to php script.
• Think Different: Either use AJAX or send the value to the same as GET, POST

Answer 1

You should take advantage of $_SESSION in this case. Now print out the drop down :

<select id="menuItem">
<?php
 $itemList = getPackCategoriesForAsideMenu();
 if(isset($itemList)){
 foreach($itemList as $u){
 echo'<option value="'.$u->pkg_cat_ddlist_id.'">'.$u->name.'</option>';
 }
 }
?>
</select>

Write the JS script :

$("#menuItem").live('change',function(){
 var val = $(this).val();
 $.post('change.php',{data:val},function(){
 // Do some 
 });
});

And create a php file named change.php :

<?php
session_start();
if(!empty($_POST['data'])){
 $_SESSION['menu_sltd'] = (int) $_POST['data']; // It makes sure that the data sent is integer / number
}
?>

Now, change your main script to :

<?php
session_start();
$menu_sltd = (!empty($_SESSION['menu_sltd']) ? $_SESSION['menu_sltd'] : 'default id'); // Default id is the default menu id if it's blank
$menuItemList = getSubPkgCategForDDList($_SESSION['menu_sltd']);
if(isset($menuItemList)){
 foreach($menuItemList as $u){
 echo'
 <p>
 <span contenteditable="true">'.$u->name.'</span>
 <button type="button" class="btn btn-danger btn-xs" onclick="deleteCategory('.$u->pkg_cat_ddlist_id.')">Delete</button>
 <button type="button" class="btn btn-success btn-xs" onclick="editCategory('.$u->pkg_cat_ddlist_id.',\''.$u->name.'\')">Save</button>
 </p>';
 }
}
?>

GOOD LUCK,, glad to help you. Don't give up

• pragmus: may be, I'm not expert in PHP, but to my mind, using SESSION isn't very good idea. I thought many time, and accepted an ajax method instead of it, at last. But may be, your method deserves respect too, I can't be sure about it, because while I'm not expert in PHP. And I vote up and accept your answer to do it best for your work. Thanks!
• Mike: Thanks, someday you'll know the use of SESSION

Answer 2

In javascript function showSubCatForMenuItem() you can set the value of selected item in some hidden field on every change event the value selected by user will get updated, then while saving the use this value that is saved in the hidden field.