向URL添加其他变量

Question

I'm trying to add additional variables to the url. Eg:

example.co.uk/searchtestingv2.php?categories=rockandpop

and add: &prices=PriceLow

example.co.uk/searchtestingv2.php?categories=rockandpop&value=PriceLow

I've tried this:

$query = parse_url($url, PHP_URL_QUERY);

// Returns a string if the URL has parameters or NULL if not
if( $query ) {
    $url .= '&categories';
}
else {
    $url .= '?categories';
}

Another thing is I've tried to add it manually ie:

http://www.example.co.uk/searchtestingv2.php?categories=rockandpop&value=PriceLow

and it doesn't work.

Here's my code:

if($_GET['categories'] == 'rockandpop') {   

        $query = "SELECT * FROM searchacts WHERE category='Rock and Pop'";   
    } 

        if($_GET['categories'] == 'tributebands') {   

        $query = "SELECT * FROM searchacts WHERE category='Tribute Bands'";   
    } 

and

if(isset($_GET['value'])) { 
    if($_GET['value'] == 'PriceLow') { 

        $query = "SELECT * FROM searchacts ORDER BY price ASC";   
    }   
    elseif($_GET['value'] == 'PriceHigh') {   

        $query = "SELECT * FROM searchacts ORDER BY price DESC";   
    }
    elseif($_GET['value'] == 'NameAZ') {   

        $query = "SELECT * FROM searchacts ORDER BY name ASC";   
    } 

    elseif($_GET['value'] == 'NameZA') {   

        $query = "SELECT * FROM searchacts ORDER BY name DESC";  

    }

    else {   

        $query = "SELECT * FROM searchacts";   
    }  

Answer 1

function UpdateUrlParam(name, value)
{
  var href = window.location.href;
  var regex = new RegExp("[&\\?]" + name + "=");
  if(regex.test(href))
  {
    regex = new RegExp("([&\\?])" + name + "=\\d+");
    window.location.href = href.replace(regex, "$1" + name + "=" + value);
  }
  else
  {
    if(href.indexOf("?") > -1)
      window.location.href = href + "&" + name + "=" + value;
    else
      window.location.href = href + "?" + name + "=" + value;
  }
}
UpdateUrlParam('value', 'priceLow);