php isset() equivalent in javascript

Question

I\'m looking for the javascript equivalent of the php function isset(). I\'ve tried the method described here at JavaScript isset() equivalent but at firebug, e

Answer 1

I think the best solution is to look in the source code of php.js:

function isset () {
    // !No description available for isset. @php.js developers: Please update the function summary text file.
    // 
    // version: 1103.1210
    // discuss at: http://phpjs.org/functions/isset
    // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: FremyCompany
    // +   improved by: Onno Marsman
    // +   improved by: Rafał Kukawski
    // *     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,
        undef;

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

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