Dropdown menu php

[fortnox007]

Hi all, I was wondering if someone knows a clean way to make a dropdown menu using just php and html with the following functionality. If someone selects a value from the dropdown options it should be visible on refresh.

So in case a have a dropdown menu with: oranges, apples, grapes and someone selects grapes and submits it, grapes should be selected.

 

I have made someonthing but it looks redundant. I think there should be something with a foreach loop or something but i can't figure it out yet.

 

Thanks in advance,

cheers!!

[rwwd]

Hi there,

 

Something like this:-

 

function Offset(){
$OffsetGap = range('0','24', '2');

$OffsetHtml = "<select name=\"Choose_offset\">";
$OffsetHtml .= "<option value=\"".(isset($_POST['Choose_offset']) ? $_POST['Choose_offset'] : '')."\">".(isset($_POST['Choose_offset']) ? $_POST['Choose_offset'] : 'Choose offset')."</option>";
foreach($OffsetGap AS $OffsetGapKey=>$OffsetGapValue){
	$OffsetHtml .= "<option value=\"".$OffsetGapValue."\">".$OffsetGapValue."</option>";
}
$OffsetHtml .= "</select>";

return $OffsetHtml;

}

 

I can't be bothered re doing this for you, but this is something that I use for something similar to what you are asking for, it seems to work, just adjust it according to your needs. Have fun.

 

Cheers,

Rw

[Psycho]

That is way more complicated than it needs to be.

 

The key is to have a defined "list" of values. This can be from a database query or from a hard-coded array. Here is a simple example:

$optionList = array('apple', 'orange', 'banana', 'pear');
$fruitOptions = '';
$selectedValue = (isset($_POST['fruit'])) ? $_POST['fruit'] : false;
foreach($optionList as $value => $label)
{
    $selected = ($value == $selectedValue) ? 'selected="selected"' : '';
    $fruitOptions .= "<option value=\"{$value}\"{$selected}>{$label}</option>\n";
}

 

Then where you have the select list in the body of your page

<select name="fruit">
<?php echo $fruitOptions; ?>
</select>

[fortnox007]

Oh wow thanks you both for the really quick respond. the first one looks pretty advanced  I have to decypher it a bit but that's good for learning. I'll try to rewrite it a bit with normal if-statements (i still have to learn alot The second looks more easier for my brains

Thanks alot guys!

[rwwd]

I could see what you were after, and this is the closest thing that I have to had without rewriting something, and to be honest I haven't got that much time, I am at work after all.

 

Good source of inspiration this place when you get stuck!

 

@mjdamato: I didn't realise that it was overkill, it suits my need, though this is an old example from something I did a while back - I just though that it scratched the itch

 

Cheers,

Rw

[Psycho]

I'll try to rewrite it a bit with normal if-statements

 

Why would you not want to use the ternary operator? It is the perfect solution when you need to set a variable to one of two values based upon a condition.

 

Here is the same code with comments added

//Array of values for the select list
$optionList = array('apple', 'orange', 'banana', 'pear');
//Variable to hold the html for the options
$fruitOptions = '';
//Assign the selected value (if it was set)
$selectedValue = (isset($_POST['fruit'])) ? $_POST['fruit'] : false;
//Iterrate through each option (uses the index key as the actual value)
foreach($optionList as $value => $label)
{
    //Set the $selected variabled based on whether the selcted option equals the current option
    $selected = ($value === $selectedValue) ? 'selected="selected"' : '';
    //Add the html for the current option to the options variable
    $fruitOptions .= "<option value=\"{$value}\"{$selected}>{$label}</option>\n";
}

EDIT: Made one change. Changed the double equal to a triple equal. The reason for doing so is that I set the $selectedValue to false if the POST value was not set. The problem was that if there is an option with a value of 0, then false would compare to 0 using double equal comparison. This isn't a problem with this particular example since 0 would be the first value. But, if there was a situation where 0 could be the 2nd or later option, then that value would be preselected even if the user did not submit a value.

 

@mjdamato: I didn't realise that it was overkill, it suits my need, though this is an old example from something I did a while back - I just though that it scratched the itch

 

I think it was overkill in the sense that there was more going on than just preselecting a value. I suspect offset gap part of the code would cause more confusion than clarification.

[fortnox007]

Why would you not want to use the ternary operator? It is the perfect solution when you need to set a variable to one of two values based upon a condition.

Well i am still kinda new to this way of writting php.

 

In both your codes i see complete new things for me:

- variables within {}

-  .=

- something that looks like an if statements with ? and :

 

Lol this small script will keep me bussy studying : ) Anyways ty both for the great help

-edit : Ill try to learn those things today : )

[fortnox007]

Oh mjdamato,

 

ty ty for your comments in your code, i just saw it ty, it really helps understanding

[rwwd]

Hi there fortnox007,

 

- variables within {}

 

This just means that he hasn't used concatenations for adding things into a string, could be achieved with double quotes and a . period.

 

-  .=

 

This is a method of building a variable, literally meaning add to

 

- something that looks like an if statements with ? and : (called a ternary operator)

 

This is just doing an if/else statement without using multiple lines of code, this will be your best friend in the world of php - I use them where ever I can, and nested ones are brilliant, though that's for another day.

 

Hope that's clarified a few things for you anyway.

 

@mjdamato: Yes, thinking about it I could have removed those parts - wasn't exactly clear there, but I was hoping that the example could have been 'modified' to suit his needs

 

Cheers,

Rw

 

[fortnox007]

They should build you both a statue

Thanks a lot for enlightening me with these faster and cleaner ways of writing. Ill try to practise with those new things today. : )

[fortnox007]

Oh a small questions i have about the {} i just tested a bit and foudn out {} cant be used within single quotes but only within double quotes.

 

But In the book I have it says that i can use variables in a double quoted string without using the special dots which are needed in a single quoted string. So to make it clear for my self; why are you using:

$fruitOptions .= "<option value=\"{$value}\"{$selected}>{$label}</option>\n";

instead of

$fruitOptions .= "<option value=\"$value\"$selected>$label</option>\n";

 

i hope this isn't the most stupid question, but it totally new for me

[rwwd]

Hi there,

 

I guess it's down to preference.

 

I would have done this:-

$fruitOptions .= "<option value=\"".$value."\"$selected>".$label."</option>\n\r";

 

But all of this will do the same thing:

 

$fruitOptions .= "<option value=\"{$value}\" {$selected}>{$label}</option>\n";

//Single quote's means that you don't need to escape the doubles
$fruitOptions .= '<option value="$value" '.$selected.'>'.$label.'</option>\n';

$fruitOptions .= "<option value=\"".$value}."\" ".$selected.">".$label."</option>\n";

 

I think I have that correct anyway

 

Just so that there is a clear divide between php & html

 

Cheers,

Rw

[Psycho]

Oh a small questions i have about the {} i just tested a bit and foudn out {} cant be used within single quotes but only within double quotes.

 

You might want to have a look at the PHP manual for strings: http://php.net/manual/en/language.types.string.php

 

Basically, when you use double quotes (or the heredocs method) to define a string, the PHP parser will interpret variables within the string. Here are a couple of examples:

$foo = 'bar';

//Double quotes
echo "The value is $foo";
//Output: The value is bar

//Single quotes
echo 'The value is $foo';
//Output: The value is $foo

 

See the difference? When using variables within quotes I always use the curly braces. The braces help to avoid problems where the variable may be misinterpreted within the string. Examples:

$foo = 'bar';
$array['index'] = 'somevalue';

echo "Variable adjacent to other 'text': $foo_underscore";
//Ouptut: Variable adjacent to other 'text': 
//The PHP is trying to parse the variable $foo_underscore which doesn't exist

echo "Variable adjacent to other 'text': {$foo}_underscore";
//Ouptut: Variable adjacent to other 'text': bar_underscore
//The curly braces define where the variable begins and ends for the PHP parser

[fortnox007]

Cool, I learned something again. I am gonna read that php manual tonight. have to eat now

thanks again you both, i am feeling like a future jedi 

 

-edit: Oh and thx for the example of the underscore I now understand it : )

[Psycho]

Woops! I was going to add another example where using curly braces is useful for array variables in a string, but decided not to at the last minute. So, disregard the array value in my example above as it has no consequence on the rest of the code.

[fortnox007]

I just read  the string parsing thing and, it's far more detailed than my book : ) thx for pointing me in the right direction