Javascript modules loading with eval()

Recently i asked to use eval() for a module function. Now i ended up doing a very weird function which does what i want. I like the idea i made it but im not so sure if this is state of the art, or more, good to build an application on.

index.html:

<script src="module.js"></script>

<script>

require('alert');

bam(); // 9
</script>

module.js:

(function () {

    var require = window.require = function (fnName) {

        var dependencies = fnName.split(' '); // load multiple dependencies etc. (not nessecairy now)

        // REAL CASE WOULD BE, TO LOAD A .JS FILE INTO A STRING VAR
        var code = 'var bam = function() { var x = 1; var y = 2; var z = (x+y)*3; alert(z); }';

        return (function () {
            window.eval(code);
        })();
    }

})();

So is this a good solution for a require function like in php if i only load and eval() files made by me?

EDIT: I modified my code and finished it now:

(function () {


"use strict"

    // include function
    var include = window.include = function (fnName, callback) {// var defining
        var dep = fnName.split(' '),
            depLen = dep.length,
            code = '',
            ajax = function (url, method, async, callback) { // ajax call to load scripts
                if (window.XMLHttpRequest) {
                    var xmlhttp = new XMLHttpRequest(); // code for IE7+, Firefox, Chrome, Opera, Safari
                }
                else {
                    var xmlhttp = new ActiveXObject( "Microsoft.XMLHTTP" ); // code for IE6, IE5
                }

                xmlhttp.open(method, url, async);
                xmlhttp.onreadystatechange = function() {
                    if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { // if scripts are loaded fire callback
                        callback( xmlhttp.responseText );
                    }
                }
                xmlhttp.send(null);
            }

        // If productionMode is set to false, use standard script tags instead of include.js
        if (include.conf.productionMode === false) {
            for (var i=0;i<depLen;i++) {
                var script = document.createElement("script");
                var path = include.conf.scriptPath + dep[i] + '.' + include.conf.scriptExtension;

                script.setAttribute("type", "text/javascript");
                script.setAttribute("src", path);

                document.getElementsByTagName('head')[0].appendChild(script);
            }

            // function looping to only fire the callback if scripts are ready
            var fn = function () {
                var state = 0;
                for (var i=0;i<depLen;i++) {
                    var objName = dep[i];
                    if ( typeof window[objName] === 'object' ) {
                        state++;
                    }
                }

                // scripts ready
                if (state === depLen) {
                    clearInterval(t);
                    callback();
                    return;
                }
            }

            // setInterval for function looping
            var t = setInterval(fn,100);
        }

        // callback is not set, so use the one liner function call as a synchronous loader
        if (typeof callback === 'undefined') {
            // function looping to only fire the callback if scripts are ready (production mode)    
            for (var i=0;i<=depLen-1;i++) {
                ajax(include.conf.scriptPath + dep[i] + '.' + include.conf.scriptExtension, 'GET', false, function(response) {      
                    code += response + ';';
                });
            }

            window.eval(code);
            return;
        }

        // function looping to only fire the callback if scripts are ready (production mode)    
        for (var i=0;i<depLen;i++) {
            ajax(include.conf.scriptPath + dep[i] + '.' + include.conf.scriptExtension, 'GET', true, function(response) {
                code = code.replace(';;;;','');
                code += response + ';;;;';
            });
        }

        // function to only fire the callback if scripts are ready
        var fn = function() {
            // scripts ready
            if (code.slice(-2) === ';;;;') {
                clearInterval(t);
                console.log(code);
                window.eval(code);
                callback();
            }
        }
        // setInterval for function looping
        var t = setInterval(function() { fn(); },0);
    }

    // include.js configuration
    include.conf = {
        productionMode  : false, // set to false for debugging
        scriptPath      : 'js/', // path to your scripts
        scriptExtension : 'js'   // script extension
    }

})();