Parameter from url with php and write it into js variable in an if condition

Question

I am trying to get a parameter from the url with php and write it into a js variable to do some jquery stuff.

my url looks like that

www.example.com/?v=12345

My Code

vnew = "<?php echo $_GET["v"];?>";
if (vnew  == null) {
myfunction();
}
else {
$(".myDiv").attr('src','newsrc');   
$(".title").html("bla");
};

if the url is like www.example.com shouldn't the value be 'null', so that my function fires? However if i set it to '12345' the else condition does not fire either.

What is wrong here? Thank you!

just if vnew = '' ? But why isn't the else condition working — Marc Ster
– Marc Ster, Commented Feb 8, 2014 at 17:32

malta · Accepted Answer · 2014-02-08 22:56:41Z

1

Change it like this:

<?php if ($_GET["v"]) { ?>
    myfunction();
<php } else { ?>
    $(".myDiv").attr('src','newsrc');   
    $(".title").html("bla");
<?php } ?>

OR

<?php 
if ($_GET["v"]) {
    echo "myfunction();";
} else {
    echo "$(\".myDiv\").attr('src','newsrc'); $(\".title\").html(\"bla\");";
} ?>

to check if your condition is working:

<?php 
if ($_GET["v"]) {
    echo "myfunction();";
} else {
    echo "Hello";
} ?>

edited Feb 8, 2014 at 22:56

answered Feb 8, 2014 at 17:33

malta

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7 Comments

malta Over a year ago

I am taking care of the condition on the server side which is always safer. Instead of closing the php each time, you may echo the text within the php.

malta Over a year ago

I have included an option where there is only 1 opening and closing php tag

malta Over a year ago

try this instead - if (isset($_GET['v']))

Marc Ster Over a year ago

hm did not change something. i don't get it

Marc Ster Over a year ago

the else condition isn't working.. if v is set. everything is fine. if not nothing happens

|

Mitya · Accepted Answer · 2014-02-08 17:32:32Z

1

It'll never be null, only an empty string. Think about what the JS output is if no value is passed:

vnew = ""; //no PHP output between the quotes, as no value found

In any case you don't need PHP to grab the var, in any case.

var tmp = location.search.match(/v=([^&]+)/), vnew = tmp ? tmp[1] : null;

In this case, the value WILL be null if no value is found.

answered Feb 8, 2014 at 17:32

Mitya

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4 Comments

Marc Ster Over a year ago

Ok now the if null query works. But not if v is set.. then nothing happens

Marc Ster Over a year ago

if i set v to '123'. It will return 'v=123,123' now

Mitya Over a year ago

Hmm, no. Try alerting vnew - if you access the file with v=12345 in the URL, your alert will be "12345". Tested.

Marc Ster Over a year ago

You are right. But why isn't my else condition working then? :/

Fven · Accepted Answer · 2014-02-08 17:40:20Z

0

Try var_dump($_GET["v"]) on the base url. Use that value in your comparison.

answered Feb 8, 2014 at 17:40

Fven

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