This question already has answers here:
How do I pass variables and data from PHP to JavaScript?
(19 answers)
Closed 8 years ago.
I'm trying to call a javascript function with one argument being a variable gotten from a drop box. This script works fine if only passed the value from the current drop box using "this.value", however when trying to pass the variable the code doesn't work. The variable is properly being populated from the value in the drop box when I use echo statements. I think the problem is with actually passing the variable to the javascript function. The function showSection(q, r) is never being called as the write statement is never executing. Any help would be appreciated. Here is my php and javascript code
echo "<select name=\"course\" onchange=\"showSection($q, this.value)\">";
If the $q or this.value are string values, you have to pass it within quotes.
echo "<select name='course' onchange='showSection(\"$q\", \"this.value\")'>";
You need to make sure inserting the value of $q doesn't produce javascript syntax errors. The reasonable way to do that is to use json_encode on the value.
After that you need to make sure both single and double quotes are escaped in that value, to keep the html correct. htmlspecialchars is used for that. In my opinion, converting both single and double quotes always (ENT_QUOTES) is the best choice.
And the end result is (I'm using heredoc syntax here, because I find it more readable):
$escaped = htmlspecialchars(json_encode($q), ENT_QUOTES);
echo <<<HTML
<select name="course" onchange="showSection($escaped, this.value);">
HTML;
Related
This question already has answers here:
what does a question mark mean before a php form action
(4 answers)
Closed 2 years ago.
Can someone explain to me what is the use of ?action=add&code= and what they do in the code below? I have tried to search it on Google but they gave me HTML action atribute instead.
<form method="post" action="index.php?action=add&code=<?php echo $product_array[$key]["code"]; ?>">
Sorry for the noob question.Thanks for the reply.
Those are called query string values or parameters, they are one of several potential parts of a URL. Each key/value pair provides information that the server-side code can use when constructing the response to send back to the client. (Or the server-side code could even simply ignore them, they have no harmful effect.)
For example, given this key/value pair on the query string:
action=add
In the server-side code you can get the value "add" by fetching it from the query string by its key:
$action = $_GET["action"];
// $action now contains the string "add"
Presumably the logic in the code would then do something based on that value.
action is the name of a "normal" GET variable $_GET['action'].
You must look in the further code to see where it appears and what it is used for.
There is no standard for that
In the url after ? we can pass the values onto another webpage which can be used further.
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How do I execute PHP that is stored in a MySQL database?
(7 answers)
Closed 4 years ago.
EDIT: This question has been edited from the original
I have a string in a database with HTML and PHP variable's inside. Some of the HTML has double quotes as if I try to use single quotes the database escapes it by adding a quote in front of it like so: ' '.
I want to query the string and assign it to variable $x. And then use eval("\$x = \"$x\";"); to parse the PHP variable, but it seems the double quote is ruining the eval(), and the variables are not parsing.
Is there a way to allow PHP to read the variable?
I am aware, but anyone reading this should also be aware that using eval() can be very dangerous!
Any help would be greatly appreciated!
If your SQL string looks like this: myVar then php:
$myVar = 'hello!';
echo $$var;
If your SQL string looks like this: 3 + 5 then php:
eval($var);
In first option we use Variable Variables
In second option we use eval to evaluate code in string.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Difference between single quote and double quote string in php
Hey I'm having trouble inserting page content into my database.
I'm trying to store:
<p class=\"heading_large\"><?php echo $Topic2C2A[data]; ?></p>
Using this code:
$sql="UPDATE event SET
data='<p class=\"heading_large\"><?php echo $Topic2C2A[data]; ?></p>'
WHERE id='2'";
But when I look at the table all I see is:
<p class="heading_large"><?php echo ; ?></p>
I've obviously escaped the HTML with slashes, is there something similar I need to do with the PHP so $Topic2C2A[data] is displayed?
I would suggest you write your $sql as:
$sql="UPDATE event SET data='<p class=\"heading_large\">".$Topic2C2A[data]."</p>' WHERE id='2'";
Your issue is related to the fact PHP is processing variables inside " (double) quotes.
You can change quotes to ' (single) or another option is to change $Topic2C2A[data] to \$Topic2C2A[data].
Did you try mysqli_real_escape_string()? It should return a fully escaped String!
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Pass a PHP string to a Javascript variable (including escaping newlines)
Access a JavaScript variable from PHP
I have a Javascript function that takes in one variable. The function has some php code inside it. I want to use this variable inside the php section of the function. I couldn't get it to work. How is it done?
The issue is that your PHP code is being rendered on the server before being served to the client. I would recommend either converting the PHP code into Javascript code or creating an AJAX call to the PHP function.
Start reading about AJAX! You will likely need to rewrite some of the code you have written but what you are attempting to accomplish is not really possible otherwise.
try with it
<script>
var whatever = "<?php echo $phpVar ?>";
</script>
This question already has answers here:
How do I pass variables and data from PHP to JavaScript?
(19 answers)
Closed 8 years ago.
<button class="addToPlaylist" onclick="javascript:myPopup(<?php echo $videos[$counter]?>);
return false;">+</button>
I have a button on an image as a html hyperlink. I want to perform different actions on hyperlink and button. The above code works whenever I do not pass the PHP variable using echo. When i pass PHP variable, the button also performs the same action as of the hyperlink, that means return false does not work.
Any idea why the return false; does not work when i pass PHP variable?
This should be:
<button class="addToPlaylist" onclick="javascript:myPopup('<?php echo $videos[$counter];?>');return false;">+</button>
Note the single quotes in myPopup. As you pass a string to myPopup, you will need to enclose it with single quotes. (Double won't work as there is already double quotes for the onclick)
I am quite sure $videos[$counter] is not numeric, but a string. In this case you have to write the quotes:
onclick="javascript:myPopup('<?php echo $videos[$counter]?>');
And make sure, $videos[$counter] doesn't contain any, something like
onclick="javascript:myPopup('<?php echo addslashes($videos[$counter])?>');
comes to mind.
onclick="javascript:myPopup("";return false;" . This should work and i think it's more clear where you have javascript code and php code.