I'm having issues with filling 3 types of form input. Radio buttons, select (drop-down list) and textarea.
<textarea name="kommentar" cols="25" rows="7" value="<?php echo "$comment";?>" required></textarea>
<select name="interesse" required>
<option disabled selected>Bitte auswählen</option>
<option>Java</option>
<option>PHP</option>
<option>C++</option>
<option>Ruby</option>
<option>SQL</option>
<option>PLSQL</option>
</select>
<fieldset>
<label for="bewertung">
<input type="radio" name="bewertung" value="1" required />1
<input type="radio" name="bewertung" value="2" required />2
<input type="radio" name="bewertung" value="3" required />3
<input type="radio" name="bewertung" value="4" required />4
<input type="radio" name="bewertung" value="5" required />5
<input type="radio" name="bewertung" value="6" required />6
</label>
</fieldset>
I need a preselected radio button, selected drop-down list entry and also the comment field should be filled (that doesn't work yet). How is it possible, to fill these with values from php variables?
<textarea> doesn't support the value attribute, echo your $comment between the <textarea></textarea> tags.
Use conditional logic to check off a radio button and select box options:
<option value="bar" name="foobar" <?php echo ($foobar == "bar" ? "selected=\"selected\"" : ""); ?>>bar</option>
<input type="radio" value="foo" name="foobar" <?php echo ($foobar == "foo" ? "checked=\"checked\"" : ""); ?> /> foo
UPDATE
Applied to your original code:
<?php
$interesse = "PHP";
$bewertung = 4;
?>
<textarea name="kommentar" cols="25" rows="7" required><?php echo "$comment";?></textarea>
<select name="interesse" required>
<option disabled>Bitte auswählen</option>
<option <?php echo ($interesse == "Java" ? "selected=\"selected\"" : ""); ?>>Java</option>
<option <?php echo ($interesse == "PHP" ? "selected=\"selected\"" : ""); ?>>PHP</option>
<option <?php echo ($interesse == "C++" ? "selected=\"selected\"" : ""); ?>>C++</option>
<option <?php echo ($interesse == "Ruby" ? "selected=\"selected\"" : ""); ?>>Ruby</option>
<option <?php echo ($interesse == "SQL" ? "selected=\"selected\"" : ""); ?>>SQL</option>
<option <?php echo ($interesse == "PLSQL" ? "selected=\"selected\"" : ""); ?>>PLSQL</option>
</select>
<fieldset>
<label for="bewertung">
<input type="radio" name="bewertung" value="1" required <?php echo ($bewertung == 1 ? "checked=\"checked\"" : ""); ?> />1
<input type="radio" name="bewertung" value="2" required <?php echo ($bewertung == 2 ? "checked=\"checked\"" : ""); ?> />2
<input type="radio" name="bewertung" value="3" required <?php echo ($bewertung == 3 ? "checked=\"checked\"" : ""); ?> />3
<input type="radio" name="bewertung" value="4" required <?php echo ($bewertung == 4 ? "checked=\"checked\"" : ""); ?> />4
<input type="radio" name="bewertung" value="5" required <?php echo ($bewertung == 5 ? "checked=\"checked\"" : ""); ?> />5
<input type="radio" name="bewertung" value="6" required <?php echo ($bewertung == 6 ? "checked=\"checked\"" : ""); ?> />6
</label>
</fieldset>
This would have the "PHP" option selected and the 4th radio button checked.
Basically, all you have to do is echo in certain content.
For textarea, we want to echo in the comment between the textarea open/close tags.
<textarea name="kommentar" cols="25" rows="7" required> <?php echo "$comment";?> </textarea>
For the radio button, you use the word "checked" (or checked="checked") to declare a checked option. You could check specific things as needed, and echo in the word checked where it should be.
<input type="radio" name="bewertung" value="1" required <?php echo "checked"; ?> />
For the select element, you use the word "selected" (or selected="selected") to declare a selected option. You could check specific things as needed, and echo in the word selected where it should be.
<option <?php echo "selected"; ?> >Java</option>