Printing PHP script as plain text using jquery - javascript

I am trying to create a preview HTML division wherein I face a challenge.
When I try to get code from the textarea and print it in the HTML, I could not see the PHP code. Here's are my codes,
HTML Where the code from textarea will be printed
<pre id='pques'></pre>
jQuery code that will take value from textarea and put in the above HTML pretty print area:
jQuery(document).ready(function($) {
setInterval(function(){
$("#pques").html($("#eques").val());
}
});
Value inside the textarea with id=eques
What will be the output of the following php code?
<div class="code"><?php $num = 1; $num1 = 2; print $num . "+". $num1 ; ?> </div>
Someone kindly help me to achieve this. I want somewhat similar functionality to the stack overflow question preview stuff.
Thank you.

The simplest way to do this is to escape the angle brackets in the PHP open and closing tags as HTML entities:
<?php .. ?> becomes <?php ... ?> - PHP will not treat this as server code and will ignore it, but the browser will display < as < and > as >. This way you don't need JavaScript to do it, you can print it directly to the page. I would advise always HTML encoding any PHP code that is input on your site, and storing it with entities rather than executable code.

As you use jquery, you can achieve this as described here
This will escape the brackets as #kallum-tanton already pointed out.

Related

adding line break into javascript from php

Please bear with me as this is not easy to explain. I have a field in a MySQL database that was put there from a form with a textarea input. It seems to me that line breaks are coded as "/n"
When I retrieve the data I can display it on the screen correctly by using the following php lines
$main_article1 = str_replace("\n", "<br />", $row[main_article]);
echo $mainarticle1;
However, now comes the tricky bit. I then want to insert that text into a scroller that uses Javascript.
The code in that script is:
var pausecontent=new Array()
pausecontent[0]='<?php echo $main_article1;?>'
I just get a blank screen.
If I remove the line breaks from the text in the database all works well - the main_article text appears in the scroller as it should - it only stops working when the line breaks are there.
Does anyone know how I can get the line breaks in the database field to go through the PHP script and appear in the scroller text in the Javascript?
I have also tried:
$main_article1 = str_replace("/n>", "%0D%0A", $row[main_article]);
but that does not work either
I hope I have made sense of what I am trying to do.
Many thanks in advance.
Tog
Here is an update
$main_article = 'This is a test<br />This is a test'
the code generated by php within the JS should be:
pausecontent[0]='This is a test<br />This is a test'
(all greyed out) but what I am getting is:
pausecontent[0]='This is a test
This is a test'
and the line break in the JS code is causing it to fail because the text is no longer greyed out after the line break
You can try the nl2br() function
$main_article1 = nl2br($row[main_article]);
also I suggest leaving a space between your code and the closing php tag (?>)
pausecontent[0]='<?php echo $main_article1; ?>'
Got it at last, after too many days headache!
I was looking at the wrong replacement theories
The answer is to use the following line:
$main_article1 = preg_replace("/\r\n|\r|\n/",'<br/>',$row[main_article]);
Now it works perfectly.
Thanks to all for your help.
Regards
Tog

Combining single and double quotes in JavaScript

I'm wondering if JavaScript has a writing format for using html elements that have both single and double quotes inside JavaScript functions. May be something like heredoc for javascript or it could be a function in jQuery.
I couldn't find a solution to my problem and will try to describe it below:
I am writing a web page on php. I have a page and there is a form in it. There is a jQuery function that appends select elements to a form. After appending, user selects some options and submit the form. (I really wanted to paste a whole code here to make it clearer, but there is a big amount of code which is not so nice, so I tried to simplify it for you, sorry for some bad code)
I have a php variable like this one (select has onchange event, showUser is a function with AJAX request):
$string = <<<EOT
<select name="sapak[]" onchange='showUser(this.value, document.getElementsByName("dereje[]")[0].value)'>
EOT;
And there are many option in between and of course closing </select>(I didn't write all the code to be shorter). A part of jQuery function that appends select to the form:
$(wrapper).append('<div> <? echo $string; ?> Del</div>');
My problem here is that in $string variable I have to use single and double quotes, and when it comes to append() function in jQuery I use quotes again. And all these give me error in browser's console Uncaught SyntaxError: Unexpected identifier, because of single quotes started at append(' , but ending at onchange=' . Is there are any smart solution for this? I thought that heredoc will be, I've googled and I think that actually there is no heredoc for javascript. May be some other formattings available?
This should work :
$(wrapper).append("<div> <? echo $string; ?> </div>");
$string = <<<EOT
<select name=\"sapak[]\" onchange=\"showUser(this.value, document.getElementsByName('dereje[]')[0].value)\">
EOT;
As #Imperative advises about character escaping

Double Nested PHP and Javascript with jQuery

I've run into a bit of a design problem. I have a webpage with a button. The page is written in php. The php outputs HTML that uses jQuery to initialize a button. When I click that button, a jquery dialog appears. The contents of the dialog are created from an object in PHP. and passed from a php object, but require formatting in Javascript, which is also passed from the php object.
A simplified version of the code would look like this:
$obj = new Custom_Object();
echo <<<EOD
<input type="button" id="button1">
<script>
$("#button1")
.button()
.click(function(){
var dialog = $("<div>" + {$obj->print()} + "</div>");
dialog.dialog();});
</script>
EOD;
with $obj->print() looking something like:
$return = "<p>Some HTML</p>";
$return .= "<script>Some Javascript to format the 'Some HTML' paragraph</script>";
return str_replace(array("\r", "\n"), '', $return);
My questions: (1) Is there some obviously better way of writing this code that just isn't occurring to me; and (2) how does the browser deal with the fact that there are two sets of \script\ tags nested inside of each other? (For some reason the code doesn't work and I am guessing that this is what is causing it, but I am not sure).
Answer to question 1:
You could just write your normal HTML and then insert the PHP values inside of it, without using a heredoc, like so:
<?php $obj = new Custom_Object(); ?>
<input type="button" id="button1">
<script>
$("#button1")
.button()
.click(function(){
var dialog = $("<div>"+<?php {$obj->print()} ?>+"</div>");
dialog.dialog();
});
</script>
Answer to question 2:
The second script tag is not being nested inside of the first, it just seems like it. The second script tag is actually being inserted in a completely different place in the DOM by jQuery after your code is interpreted.
If you think it may be getting interpreted incorrectly, you should try wrapping your JavaScript in CDATA tags and escaping quotes properly inside of the string generated by PHP.
You can achieve a lot more stability by simply "closing" your php tag and re-opening it later in the document.
So for instance, you could have:
<?php
$obj = new Object();
?>
<input type="button" id="button1">
<script>
$("#button1").button().click(function(){
var dialog = $("<div><?php $obj->print(); ?></div>");
dialog.dialog();
});
</script>
Just remember that what ever you output from $obj->print(); will need to have double-quotation marks escaped
Most modern browsers are able to work very well with more than 1 tag.
I'd also advise that you set the script type by changing your opening tag to .

Display Javascript/Html/PHP as text

I am trying to display code on a webpage, just as text, for the user to view. The code snippet is obtained from a database, input using a form, and put in a div using PHP. Jquery is then used to replicate the html of that div in another element. The code from the database will never be executed; I am basically just making notes.
Code example: alert('Hello'); (could be PHP or html)
What is the best way of displaying this as text, in my browser?
Filter it somehow using PHP as it is input using a form.
Use of HTML tags (pre, xmp tags, CDDATA).
Convert special characters with some javascript function.
combination of the above.
Example of use below.
PHP
$inputQuery="SELECT x FROM y";
$input = mysqli_query($dbc,$inputQuery);
$row = mysqli_fetch_array($input);
//no issues above, just used to clarify the issue. If $input is javascript code, the below doesn't work.
echo'
<div id="inputCode">'.$row["x"].'</div>';
JAVASCRIPT/JQUERY
var inputCode = $("#inputCode").html();
$( "#displayInputCode").html(inputCode);
Use htmlentities() to convert all the HTML special characters to entities, so they won't be executed:
echo'
<div id="inputCode">'.htmlentities($row["x"]).'</div>';
For HTML you can use htmlentities() which would protect against malicious data like <script> tags that include bad stuff; and for PHP you're already fine since echo'ing PHP code does not execute it (and browsers doesn't execute PHP code either).
Example code :
echo '<div id="inputCode">'.htmlentities($row["x"]).'</div>';

Trying to parse webpage using php

I am trying to parse a webpage and print out a table which is on the webpage. I am using php_simple_html dom parser. However, when I try to parse the table off the webpage, all the javascript commands to output the table get turned into comments within the php:
<html>
<script type="text/javascript" src="jquery.js"></script>
<?php
include 'crawling/simple_html_dom.php';
$html = file_get_html('http://uiucfreefood.com/');
$ret = $html->find('body', 0)->find('div', 10)->find('table',0); //gets to the table tag
echo $ret; // nothing is echoed out because the original webpage uses jscript commands to write the table to the page but these commands get turned to comments for some reason.
?>
</html>
When I inspect the element of the page where I am echoing the parsed information I am able to see that the table tag with all the info is in there but the jscript commands have been turned into comments. Is there a way for me to just grab the info and echo it out myself? I tried adding another ->find('tbody'); at the end of the parse command but it doesn't do anything. Any advice is appreciated. Thanks.
EDIT: You can try this code out yourself if you download the simple_html_dom.php and include it in your php file. Source: http://sourceforge.net/projects/simplehtmldom/files/
EDIT: Just noticed something really important. The javascript commands are commented out in the original webpage also. Instead, the original webpage is using a javascript function to print out the table which I do not have defined. Writing that function myself should fix the issue.
EDIT: yup, that worked.
Try using file_get_content instead of get HTML and see if that works. Honestly, depending on your needs, you should code your own parser. It is not that hard to write a parser for the table scan and display.
You will just need the following;
$array = split("<table>", $content);
$boolPlaceHolder = false;
and you can then set the placeholder to true when you encounter this way you can scan through the chars of the content and grab the table.
Hope this helps.

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