Not sure what's wrong with my code - php

Question

I'm passing a date input using php $_GET
<form action="trigger_date.php" method="get">
Enter Project Turnover date (mm/dd/yy): <input type="string" name="date"> <input type="submit">
In the trigger_date.php takes this as
<?php $turnover_date = $_GET['date']; ?>
I do some math to compare it to today's date
<?php
$project_turnover = strtotime($turnover_date);
$project_turnover = date ("m/d/y", $project_turnover);
?>
<?php
$datetime1 = date_create($today);
$datetime2 = date_create($project_turnover);
$wks_to_turnover = date_diff($datetime1, $datetime2); // taking the difference between today and project turnover date
$wks_to_turnover = $wks_to_turnover->format('%R%a');
$wks_to_turnover = ($wks_to_turnover/7);
$wks_to_turnover = round($wks_to_turnover,1); //with input of 5/1/14 this should be roughly 24 wks
?>
Here's where I'm stumped, my styling is:
<?php
if ($wks_to_turnover > 2) {
echo $date_green; // colors the background green
} elseif (2 > $wks_to_turnover && $wks_to_turnover > 0) {
echo $date_yellow; // colors the background yellow
} elseif (0 >= $wks_to_turnover) {
echo $date_red; //colors the background red
} ?>;
But even if (24 > 2) it's still coloring as red

Answer 1

Note that <input type="string" /> is not valid HTML -- you're looking for type="text"
date_create accepts several different formats of dates. The m/d/y format, which you're using on the input date, is bad form because it is ambiguous. Per the manual:
Note:
Dates in the m/d/y or d-m-y formats are disambiguated by looking at
the separator between the various components: if the separator is a
slash (/), then the American m/d/y is assumed; whereas if the
separator is a dash (-) or a dot (.), then the European d-m-y format
is assumed.
To avoid potential ambiguity, it's best to use ISO 8601 (YYYY-MM-DD)
dates or DateTime::createFromFormat() when possible.
Use a standardized date format that is supported by the Date object. It may not be the cause of your issue, but it is good to be unambiguous in code.
I'm not completely sure why you turn the input into a UNIX timestamp and then back to a formatted date. You could simply use the formatted date you get from input, which appears to be in a supported format, and deal with any errors that may generate.
Finally, your math produces a negative number. That's one reason why your logic fails to act as you expect. You can reverse the order of arguments passed to date_diff, OR use abs to get the absolute distance between the two dates. I went with abs, which makes the code not care if the 2 weeks is in the past or in the future. I don't know what you're doing here -- maybe the sign matters. If so, reverse the order of arguments passed to date_diff
(edit: OP clarified abs would not suite his need, adjusted accordingly)
Putting it together, I would suggest something like this:
$datetime1 = date_create('now');
$datetime2 = date_create(
array_key_exists(
'date',
$_GET
) ? $_GET['date'] : 'invalid'
);
if (!$datetime2)
die('invalid date');
$wks_to_turnover = date_diff($datetime2, $datetime1);
$wks_to_turnover = $wks_to_turnover->format('%R%a');
$wks_to_turnover = ($wks_to_turnover/7);
$wks_to_turnover = round($wks_to_turnover,1);be roughly 24 wks
if ($wks_to_turnover <= 0) {
echo 'green';
} elseif ($wks_to_turnover < 2 && $wks_to_turnover > 0) {
echo 'yellow';
} else {
echo 'red';
}
I also adjusted the final block of ifs -- if weeks is less than or equal to zero, green, if less than two but greater than 0 yellow, otherwise red.
Try it: http://codepad.viper-7.com/kLN5jk
Documentation
strtotime - http://www.php.net/manual/en/function.strtotime.php
DateTime::__construct - http://www.php.net/manual/en/datetime.construct.php
Date formats - http://www.php.net/manual/en/datetime.formats.date.php
date (documents format strings) - http://php.net/manual/en/function.date.php
abs - http://www.php.net/manual/en/function.abs.php

Answer 2

I tried your code and it return red when i pass "non numerical value" so , i tried
echo (int)$wks_to_turnover;
and it returned '0' , the reason because the date not returned as integer yet.
a quick fix for that using your approach
replace that line :
$wks_to_turnover = date_diff($datetime1, $datetime2);
with that :
$wks_to_turnover = strtotime($datetime1)-strtotime($datetime2);
it'll return the difference in seconds , you can handle it from here