Rendering javascript code in php document

Question

I'm a beginner to PHP and I have a quick question. Is it possible to have javscript code injected into a document through php?

For example, suppose I wanted to inject a button that called a function after a form is filled out:

<html>
<head>
  <script type = text/javascript>
  function func() {
  ...
  }
  </script>
</head>
<body>

<form action = 'welcome.php' method = 'post>
Name: <input type = 'text' name = 'fname' />
<input type = 'submit' value = 'submit' />
</form>

<?php
if (isset($_POST['fname'])) {
   echo '<input type = button onclick = func />'
}
?>

</body>
</html>

Would this work? If not, why not?

Any help would be great

It will work, providing you close your string inside the if(); PHP is a templating language after all. — Bojangles
– Bojangles, Commented Dec 5, 2011 at 17:08

Manse · Accepted Answer · 2011-12-05 17:15:43Z

1

Will work fine - just remember to close your quoted strings :

<form action='welcome.php' method='post'> // add ' here
Name: <input type='text' name='fname' />
<input type='submit' value='submit' />  // removed a couple of spaces (not required)
</form>

<?php
if (isset($_POST['fname'])) {
   echo '<input type="button" onclick="func" />';   // added some quotes and a semicolon
}
?>

I have removed the spaces between the attributes and the values in HTML from type = "something" to type="something" although I can't find the "official" specification on this. It seems that the spaces are perfectly valid ...I think its my personal preference to have no white space there .....

edited Dec 5, 2011 at 17:15

answered Dec 5, 2011 at 17:10

Manse

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1 Comment

Leonard Over a year ago

Don't forget to add a trailing semicolon to the echo statement!

Matt H · Accepted Answer · 2011-12-05 17:14:04Z

0

Try:

echo '<input type="button" onclick="' . $_POST['fname'] . '" />';

SAMPLE

If fname=doSomething then use:

echo '<input type="button" onclick="' . $_POST['fname'] . '()" />';

and your rendered HTML would be:

<input type="button" onclick="doSomething()" />

Then you'd just need your function somewhere:

<script>
  function doSomething() { }
</script>

edited Dec 5, 2011 at 17:14

answered Dec 5, 2011 at 17:08

Matt H

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5 Comments

dopatraman Over a year ago

@Matt_H-- how is the function called if onclick calls the POST variable?

Matt H Over a year ago

Added an example of what it would look like, also adding the ()

dopatraman Over a year ago

@Matt_H--I think theres some slight confusion. 'fname' is the input into the text box, not the name of the function.

Matt H Over a year ago

I know - I'm assuming the fname POST variable holds the name of the function you are trying to call.

Tim G Over a year ago

FYI, if you do this, then a person who submits your form can choose any function they want to run simply by typing it into a form field that's POST'd to your php script. There's too much confusion here.

Blender · Accepted Answer · 2011-12-05 17:08:46Z

0

If your current page is welcome.php and you ran this code, you would press the Submit button and the page would reload and have your new button.

But the best way to see whether this works for you or not is to run it. Why don't you try that first?

answered Dec 5, 2011 at 17:08

Blender

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