How to echo javascript into current html page from external php file

Question

Let's say I'm currently browsing mypage.html, which in its header has a link to the following js file:

<script language="JavaScript" type="text/javascript" src="jsfile.js"></script>

In jsfile.js, there's a function keyup() that is executed when the user types something into #searchbar, whose value is then stored in search = $(#searchbar).val();

I then pass this value on to search.php as follows:

$.post( "search.php", { searchval: search }, function(sentdata){
    console.log(sentdata);
});

where the content of search.php reads:

<?php
if(isset($_POST[searchval])){
        $search = $_POST[searchval];
    echo "input value is $search";
    echo "<script type='text/javascript'> alert('its working') </script> ";
}
?>

However, instead of an alert pop up (or anything else that would normally be executed in JS), the second echo simply prints " alert('its working') " into the console. How can I modify search.php to allow it to inject actual js into myfile.html? Note that I've also tried wrapping the js code in tag.

Related question: why is it that when I omit console.log(sentdata), search.php does no longer echo anything into the console?

search/check for jQuery.ajax with dataType: 'jsonp' option. bob.ippoli.to/archives/2005/12/05/remote-json-jsonp — Jigar
– Jigar, Commented Aug 14, 2015 at 5:08

user4035 · Accepted Answer · 2015-08-14 05:06:15Z

1

How I can modify search.php to allow it to inject actual js in myfile.html?

First of all, you need to modify your javascript file:

$.post( "search.php", { searchval: search }, function(sentdata){
    eval(sentdata);
});

And no need for javascript tags, just echo a valid Javascript code:

if(isset($_POST[searchval])){
    echo "alert('its working');";
}

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/eval

answered Aug 14, 2015 at 5:06

user4035

24k11 gold badges69 silver badges101 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

ephemeral Over a year ago

despite the provided explanation, I don't quite see why that first modification was necessary. isn't the purpose of function(sentdata) simply to return something on successful execution of $.post?

user4035 Over a year ago

@ephemeral You get a string from server. Javascript doesn't know whether it's a code or not. You must execute it, eval is used for this.

Manoj Dhiman · Accepted Answer · 2015-08-14 05:33:42Z

0

you can do this

$.post( "search.php", { searchval: search }, function(data){
    alert(data);  // this will alert the data which will print on search.php
});

and in the php file echo the data you want to print like

if(isset($_POST[searchval])){
    echo 'its working. i got'.$_POST[searchval];
}

answered Aug 14, 2015 at 5:33

Manoj Dhiman

5,1616 gold badges32 silver badges71 bronze badges

Collectives™ on Stack Overflow

How to echo javascript into current html page from external php file

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related