I've been wondering this for a while since I started PHP. Some sites use filtering options. Sometimes some of those filters are completely random. For example someone might be viewing: products.php?c=1&p=1&s=100
In that example, let's assume c
is the category, p
is the page and s
is the start price.
If the viewing user were to change the start price or flip to the next page using a hyperlink, how would one change only a single $_GET[]
variable while leaving the others untouched. I do have a small script in PHP to obtain the current URI however, I just can't figure out how I'd change only that variable while keeping the others untouched and refresh the page? I've looked at substr()
, strpos()
, and ereg_replace()
and I just can't figure it out!
I am really sorry if this is a dumb question, I feel like I've missed something really easy that can fix this but I'm genuinely stuck guys.
Thanks so much in advance! Mike.
It depends on whether or not you're in a form or a URL.
If you're in a form it's easy because the user changes the input field they want changed and the others stay there:
<form>
<input type="p" value="1" />
<input type="c" value="1" />
<input type="s" value="100" />
<input type="submit" />
</form>
The problem with the URL based method is you would have to set the url for each one like this:
<a href="?p=1&c=1&s=1">$1 Starting Price</a>
<a href="?p=1&c=1&s=10">$10 Starting Price</a>
<a href="?p=1&c=1&s=100">$100 Starting Price</a>
You'd have to do this to make it dynamic:
<a href="?p=<?php echo urlencode($_GET['p']) ?>&c=<?php echo urlencode($_GET['c']) ?>&s=1">$1 Starting Price</a>
That's a lot of typing for all of your links. You could make a PHP function to handle changing the one value like this:
function genUrl($newKey, $newVal) {
$url = '?';
foreach ($_GET as $key => $val) {
if ($url != '?') {
$url .= '&';
}
$url .= urlencode($key) . '=' ($key == $newKey ? $newVal : urlencode($val));
}
return $url;
}
And your html would look like this:
<a href="<?php echo genUrl('s', 1) ?>">$1 Starting Price</a>
<a href="<?php echo genUrl('s', 10) ?>">$1 Starting Price</a>
<a href="<?php echo genUrl('s', 100) ?>">$1 Starting Price</a>