如何将 php date_diff 值转换为 javascript integer？

Question

I'm trying to use the difference between two dates to help me draw lines on an HTML canvas . I generate one date in PHP and extract the other which is stored in an SQL database

When I keep everything in PHP the echo'd output is exactly what I expect. However, when I json_encode the output, which I expect to be an integer, to use to draw the shape I want on the canvas , a completely different number is presented from javascript .

I'm pretty sure it has to do with the json encoding... but I haven't been able to find any reference about how to do this properly.

Here's the PHP I use to grab, format, and create a date difference output:

$sdt = new DateTime($row['sdate']);
$today = new DateTime('now');

$sdiff = date_diff($sdt, $today);
$sdelta = $sdiff->format("%a");

If I keep all of this in PHP and either echo the variable or echo the json_encode variable I get the expected answer, which is 34.

echo $sdelta;

results in 34

echo json_encode($sdelta);

results in "34";

echo json_decode($sdelta);

results in 34;

However when I assign this value to a javascript variable and test the result of the assignment:

var diffdt = <?php echo json_encode($sdelta); ?>;
alert(diffdt);

The alert popup shows 199.

If anybody could help me with this issue, I'd be eternally grateful.

---

Extra information...

• Column type for sdate is DATE

• query I'm executing is to get the data is:

   $stmt = $link->prepare("SELECT * FROM register WHERE id =? "); $stmt->bind_param("i", $id); $stmt->execute(); $result = $stmt->get_result(); $num = $result->num_rows; $row = $result->fetch_assoc(); var_dump($row['sdate']);

• Number of rows is 1.
• vardump result is: string(10) "2019-09-27"

Answer 1

Must use "Number(your_number)" method I used here,see bottom line:

<script type="text/javascript">

    // To set two dates to two variables 
    var date1 = new Date("06/30/2019"); 
    var date2 = new Date("07/30/2019");

    // To calculate the time difference of two dates 
    var Difference_In_Time = date2.getTime() - date1.getTime();

    // To calculate the no. of days between two dates 
    var Difference_In_Days = Difference_In_Time / (1000 * 3600 * 24); 

    console.log(Number(Difference_In_Days));
</script>

Answer 2

Ended up resolving this issue by moving php code outside some of the javascript I had written. Problem was from a for loop I had implemented that updated javascript values from the php loop. This was adding up the result. None of my code actually changed, it was just rearranged.

Didn't think this was an issue since the for loop was doing it's job for what it was designed.

Thanks everyone for your help. It allowed me to eliminate most of the other potential issues.

Answer 3

airider74 When you say that PHP shows the correct data but JS does not, what are you using to display the values-- ie console/terminal/browser etc. ? Are they both using UTF8? Something you might try is encoding the output from the PHP via urlencode() and then decode it in JS via decodeURI().

PHP:

echo urlencode(dIffdt);

JS:

var diffdt = "37";  alert( decodeURI(diffdt) );

Or try base64 encoding.

PHP:

echo base64_encode(diffdt);

JS:

var diffdt = "37";  alert( btoa(diffdt) );

I am thinking possibly your data is ASCII coming out of the server, but JS uses UTF8 by default (as do most modern browsers in a more general sense).

Answer 4

You need to set the variable without the json_encode, so it would be:

var diffdt = <?php echo $sdelta; ?>;
alert(diffdt);