unable to write javascript inside the php page - php

Question

i have written a javascript inside the php file, but while calling it from my main page like this
<script type="text/javascript" src="<?php echo base_url() . 'js/inf-scroll/javascript_showuserinst.php' ?>"> </script>
Problem: if i see in the javascript_showuserinst.php file a line as $.post('/instruction/show_user_inst/<?php echo $userid; ?>', {
here <?php echo $userid; ?> is giving me problem. Is that line syntax is correct?
I see the view source its showing <b>Notice</b>: Undefined variable: userid in <b>D:\xampp\htdocs\js\inf-scroll\javascript_showuserinst.php</b> on line <b>46</b><br />
But if i copy & paste the same js content in the main page without calling it from external file, it works perfectly.
javascript_showuserinst.php
Header("content-type: application/javascript");
?>
(function($) {
$.fn.scrollPagination = function(options) {
var settings = {
nop : 10, // The number of posts per scroll to be loaded
offset : 0, // Initial offset, begins at 0 in this case
error : 'No More Data To Display!', // When the user reaches the end this is the message that is
// displayed. You can change this if you want.
.............
.............

Answer 1

JavaScript files are expected to contain JavaScript.
Your JavaScript file contains a fragment of HTML.
Don't include HTML <script> tags in a JavaScript file.

Answer 2

<?php
echo "<script type='text/javascript' src='".base_url()."js/inf-scroll/javascript_showuserinst.php"."'></script>"
?>

Answer 3

This must be in your PHP Script File
<script type="text/javascript" src="<?php echo base_url() . 'js/inf-scroll/javascript_showuserinst.php' ?>"> </script>
Now javascript_showuserinst.php can be like below
(function($) {
$.fn.scrollPagination = function(options) {
var settings = {
nop : 10, // The number of posts per scroll to be loaded
offset : 0, // Initial offset, begins at 0 in this case
error : 'No More Data To Display!', // When the user reaches the end this is the message that is
// displayed. You can change this if you want.
delay : 500, // When you scroll down the posts will load after a delayed amount of time.
// This is mainly for usability concerns. You can alter this as you see fit
scroll : true // The main bit, if set to false posts will not load as the user scrolls.
// but will still load if the user clicks.
}
// Extend the options so they work with the plugin
if(options) {
$.extend(settings, options);
}
// For each so that we keep chainability.
return this.each(function() {
// Some variables
$this = $(this);
$settings = settings;
var offset = $settings.offset;
var busy = false; // Checks if the scroll action is happening
// so we don't run it multiple times
// Custom messages based on settings
if($settings.scroll == true) $initmessage = 'No more data to show';
else $initmessage = 'Click for more';
// Append custom messages and extra UI
$this.append('<div class="content"></div><div class="loading-bar">'+$initmessage+'</div>');
function getData() {
// Post data to ajax.php
$.post('/instruction/show_user_inst/<?php echo $userid; ?>', {
action : 'scrollpagination',
number : $settings.nop,
offset : offset
}, function(data) {
// Change loading bar content (it may have been altered)
$this.find('.loading-bar').html($initmessage);
// If there is no data returned, there are no more posts to be shown. Show error
if(data == "") {
$this.find('.loading-bar').html($settings.error);
}
else {
// Offset increases
offset = offset+$settings.nop;
// Append the data to the content div
$this.find('.content').append(data);
// No longer busy!
busy = false;
}
});
}
getData(); // Run function initially
// If scrolling is enabled
if($settings.scroll == true) {
// .. and the user is scrolling
$(window).scroll(function() {
// Check the user is at the bottom of the element
if($(window).scrollTop() + $(window).height() > $this.height() && !busy) {
// Now we are working, so busy is true
busy = true;
// Tell the user we're loading posts
$this.find('.loading-bar').html('Loading...');
// Run the function to fetch the data inside a delay
// This is useful if you have content in a footer you
// want the user to see.
setTimeout(function() {
getData();
}, $settings.delay);
}
});
}
// Also content can be loaded by clicking the loading bar/
$this.find('.loading-bar').click(function() {
if(busy == false) {
busy = true;
getData();
}
});
});
}
})(jQuery);
Try it out