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@NogDogOct 21.2005 — #When you submit a form to a PHP page, a special global array calle $_POST is populated with all the values sent by the form. The array key for each value is the name of the form element. So in your example, the value of the input field which you have named "var" (name=var) is stored in the array element $_POST['var']. Depending on the settings under which PHP is running on your web host -- specifically if "register_globals" has been turned on -- then the variable $var is also created and contains that same value. For best script portability as well as avoidance of namespace problems, it would really be best for you to use $_POST['var'] in your script instead of $var, or else explicitly set $var = $_POST['var'] before using it.
Anyway, until you actually submit the form, nothing is populated in the $_POST array or its related register_global variable $var. Therefore it has a null or empty value when referenced.
Therefore, a better way to write that last "echo" line of the script would be:
Also, unless there is other stuff going on in the script we're not be shown, I see no reason for the use of JavaScript (especially since the page will therefore not work if Javascript is not enabled on the user's browser).
js in php script
When this script is called for 1st time, var variable is not initialized (Value: ).
In the second pass (submit) it is.
[code=php]
<html>
<head>
<title>TITLE</title>
</head>
<body>
<script language=”Javascript1.2″>
<!–//
document.write(‘<form method=POST action =”<? echo $PHP_SELF; ?>”>’);
document.write(‘<input type=hidden name=var value=29>’);
//–>
</script>
<input type=submit value=Get><p>
</form>
<?
echo “Value: $var”;
?>
</body>
</html>
It’s a bit confusing, because during the second pass the same JS code is performed, that is, document.write function performs the same writing of html code, before the php part is executed.
What’s the difference btw the 1st and 2nd pass?
Thanks
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@NogDogOct 21.2005 — #When you submit a form to a PHP page, a special global array calle $_POST is populated with all the values sent by the form. The array key for each value is the name of the form element. So in your example, the value of the input field which you have named "var" (name=var) is stored in the array element $_POST['var']. Depending on the settings under which PHP is running on your web host -- specifically if "register_globals" has been turned on -- then the variable $var is also created and contains that same value. For best script portability as well as avoidance of namespace problems, it would really be best for you to use $_POST['var'] in your script instead of $var, or else explicitly set $var = $_POST['var'] before using it.Anyway, until you actually submit the form, nothing is populated in the $_POST array or its related register_global variable $var. Therefore it has a null or empty value when referenced.
Therefore, a better way to write that last "echo" line of the script would be:
[code=php]
if(!empty($_POST['var'])) # if form has submitted the field and it's not empty
{
echo "<p>Value: {$_POST['var']}</p>n"; # use {} for array value within "..."
}
else
{
echo "<p>Please enter a value above then click the Get button.</p>n";
}
[/code]Also, unless there is other stuff going on in the script we're not be shown, I see no reason for the use of JavaScript (especially since the page will therefore not work if Javascript is not enabled on the user's browser).