JavaScript equivalent of this simple php...

Question

Hi, please can somebody let me know how to do the following PHP in JavaScript. The vaibles in PHP are Parameters in Javascript. If all three Parameters are set then I would like a PHP script to execute:

<?php     
if isset($nation,$service,$slider)
    {
//execute php script
    }       
?>

Thanks for looking, and maybe helping!

To clear any confusion, I require all the PHP above to be converted into it JavaScript equivalent.

On top of this I would like a way of executing a PHP script within the JavaScript if all 3 Parameters are set.

Answer 1

From what I understand you are trying to do an AJAX call. If you were to use a framework like jQuery, the code would be something like:

if ((typeof nation != 'undefined') && (typeof service != 'undefined') && (typeof slider != 'undefined')) {
    $.get("<your script>", function(data){
         alert("Data Received: " + data);
    });
}

If this is not what you are looking for, please rephrase your question.

Answer 2

Haven't tested, but looks right:

function isset(variable_name){
  return(typeof(window[variable_name])!='undefined');
}

Note that variable_name is not a variable itself, but it's name.

Answer 3

Assuming none of your variables have a zero or null value, for example, if they're all strings, the shortest way to write variable checks is to just use them:

function blah (nation, service, slider)
{
    if (nation && service && slider)
    {
        // do something...
    }
}

If any of those vars have the value 0, false or null when set then this would not be the correct method. If you want the equivalent of the isset function, you could use this:

function isset()
{
    for (var i=0, l=arguments.length; i < l; i++)
    {
        if (typeof arguments[i] == "undefined" || typeof arguments[i] == "null")
            return false;
    }
    return true;
}

Use it the same as you would the php function, e.g. isset(nation,service,slider);

Answer 4

Check out the great phpjs.org stuff. It's a port of PHP functions into JavaScript.

The isset() function:

function isset () {
    // http://kevin.vanzonneveld.net
    // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: FremyCompany
    // +   improved by: Onno Marsman
    // *     example 1: isset( undefined, true);
    // *     returns 1: false
    // *     example 2: isset( 'Kevin van Zonneveld' );
    // *     returns 2: true

    var a=arguments, l=a.length, i=0;

    if (l===0) {
        throw new Error('Empty isset'); 
    }

    while (i!==l) {
        if (typeof(a[i])=='undefined' || a[i]===null) { 
            return false; 
        } else { 
            i++; 
        }
    }
    return true;
}

Usage:

allVarsAvailable = isset(nation,service,slider);