Javascript settype : Variable handling : PHP functions in JavaScript JAVASCRIPT TUTORIALS

function settype (vr, type) {
   // http://kevin.vanzonneveld.net
    // +   original by: Waldo Malqui Silva
    // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +    revised by: Brett Zamir
    // %        note 1: Credits to Crockford also
    // %        note 2: only works on global variables, and "vr" must be passed in as a string
    // *     example 1: foo = '5bar';
    // *     example 1: settype(foo, 'integer');
    // *     results 1: foo == 5
    // *     returns 1: true
    // *     example 2: foo = true;
    // *     example 2: settype(foo, 'string');
    // *     results 2: foo == '1'
    // *     returns 2: true
    var is_array = function (arr) {
        return typeof arr === 'object' && typeof arr.length === 'number' &&
                    !(arr.propertyIsEnumerable('length')) &&
                    typeof arr.splice === 'function';
    };
    var v, mtch, i, obj;
    v = this[vr] ? this[vr] : vr;
    
    try {
        switch(type) {
            case 'boolean':
                if (is_array(v) && v.length === 0) {this[vr]=false;}
                else if (v === '0') {this[vr]=false;}
                else if (typeof v === 'object' && !is_array(v)) {
                    var lgth = false;
                    for (i in v) {
                        lgth = true;
                    }
                    this[vr]=lgth;
                }
                else {this[vr] = !!v;}
                break;
            case 'integer':
                if (typeof v === 'number') {this[vr]=parseInt(v, 10);}
                else if (typeof v === 'string') {
                    mtch = v.match(/^([+-]?)(\d+)/);
                    if (!mtch) {this[vr]=0;}
                    else {this[vr]=parseInt(v, 10);}
                }
                else if (v === true) {this[vr]=1;}
                else if (v === false || v === null) {this[vr]=0;}
                else if (is_array(v) && v.length === 0) {this[vr]=0;}
                else if (typeof v === 'object') {this[vr]=1;}

                break;
            case 'float':
                if (typeof v === 'string') {
                    mtch = v.match(/^([+-]?)(\d+(\.\d+)?|\.\d+)([eE][+-]?\d+)?/);
                    if (!mtch) {this[vr]=0;}
                    else {this[vr]=parseFloat(v, 10);}
                }
                else if (v === true) {this[vr]=1;}
                else if (v === false || v === null) {this[vr]=0;}
                else if (is_array(v) && v.length === 0) {this[vr]=0;}
                else if (typeof v === 'object') {this[vr]=1;}
                break;
            case 'string':
                if (v === null || v === false) {this[vr]='';}
                else if (is_array(v)) {this[vr]='Array';}
                else if (typeof v === 'object') {this[vr]='Object';}
                else if (v === true) {this[vr]='1';}
                else {this[vr] += '';} // numbers (and functions?)
                break;
            case 'array':
                if (v === null) {this[vr] = [];}
                else if (typeof v !== 'object') {this[vr] = [v];}
                break;
            case 'object':
                if (v === null) {this[vr]={};}
                else if (is_array(v)) {
                    for (i = 0, obj={}; i < v.length; i++) {
                        obj[i] = v;
                    }
                    this[vr] = obj;
                }
                else if (typeof v !== 'object') {this[vr]={scalar:v};}
                break;
            case 'null':
                delete this[vr];
                break;
        }
        return true;
    } catch (e) {
        return false;
    }
}