diff --git a/.eslintrc b/.eslintrc
index 71c0c4591..62d35f5e5 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -17,7 +17,7 @@
     "no-shadow": 0,
     "no-loop-func": 0,
     "eol-last": 0,
-    "no-use-before-define": 2,
+    "no-use-before-define": 0,
     "new-cap": 0,
     "no-constant-condition": 0,
     "no-redeclare": 0,
@@ -37,4 +37,4 @@
     "node": true,
     "amd": true
   }
-}
\ No newline at end of file
+}
diff --git a/src/goo/scriptpack/ScriptHandler.js b/src/goo/scriptpack/ScriptHandler.js
index 564f44155..ce6ab9d12 100644
--- a/src/goo/scriptpack/ScriptHandler.js
+++ b/src/goo/scriptpack/ScriptHandler.js
@@ -537,54 +537,11 @@ define([
 		});
 	};
 
-	// The allowed types for the script parameters.
-	var PARAMETER_TYPES = [
-		'string',
-		'int',
-		'float',
-		'vec2',
-		'vec3',
-		'vec4',
-		'boolean',
-		'texture',
-		'sound',
-		'camera',
-		'entity',
-		'animation'
-	];
-
-	// Specifies which controls can be used with each type.
-	var TYPE_CONTROLS = (function () {
-		var typeControls = {
-			'string': ['key'],
-			'int': ['spinner', 'slider', 'jointSelector'],
-			'float': ['spinner', 'slider'],
-			'vec2': [],
-			'vec3': ['color'],
-			'vec4': ['color'],
-			'boolean': ['checkbox'],
-			'texture': [],
-			'image': [],
-			'sound': [],
-			'camera': [],
-			'entity': [],
-			'animation': []
-		};
-
-		// Add the controls that can be used with any type to the mapping of
-		// controls that ca be used for each type.
-		for (var type in typeControls) {
-			Array.prototype.push.apply(typeControls[type], ['dropdown', 'select']);
-		}
-
-		return typeControls;
-	})();
-
 	/**
 	 * Load an external script
 	 */
 	function loadExternalScript(script, scriptElem, url) {
-		return PromiseUtils.createPromise(function (resolve, reject) {
+		return PromiseUtils.createPromise(function (resolve) {
 			var timeoutHandler;
 			var handled = false;
 
@@ -624,41 +581,6 @@ define([
 		});
 	}
 
-	var TYPE_VALIDATORS = {
-		string: function (key, value) {
-			if (typeof value !== 'string' || value.length === 0) {
-				return { message: 'Property "' + key + '" must be a non-empty string' };
-			}
-		},
-		number: function (key, value) {
-			if (typeof value !== 'number') {
-				return { message: 'Property "' + key + '" must be a number' };
-			}
-		},
-		boolean: function (key, value) {
-			if (typeof value !== 'boolean') {
-				return { message: 'Property "' + key + '" must be a boolean' };
-			}
-		},
-		array: function (key, value) {
-			if (!(value instanceof Array)) {
-				return { message: 'Property "' + key + '" must be an array' };
-			}
-		}
-	};
-
-	var PROPERTY_VALIDATORS = [
-		{ name: 'key', validator: TYPE_VALIDATORS.string },
-		{ name: 'name', validator: TYPE_VALIDATORS.string },
-		{ name: 'control', validator: TYPE_VALIDATORS.string },
-		{ name: 'min', validator: TYPE_VALIDATORS.number },
-		{ name: 'max', validator: TYPE_VALIDATORS.number },
-		{ name: 'scale', validator: TYPE_VALIDATORS.number },
-		{ name: 'decimals', validator: TYPE_VALIDATORS.number },
-		{ name: 'precision', validator: TYPE_VALIDATORS.number },
-		{ name: 'exponential', validator: TYPE_VALIDATORS.boolean }
-	];
-
 	/**
 	 * Validates every property of a parameter defined by a user script.
 	 * Exposed as a static method only for testing purposes.
@@ -666,33 +588,30 @@ define([
 	 * @param parameter
 	 * @returns {{message: string}|undefined} May return an error
 	 */
-	ScriptHandler.validateParameter = function (parameter) {
-		// treat key separately; this needs to always be defined
-		if (typeof parameter.key !== 'string' || parameter.key.length === 0) {
-			return { message: 'Property "key" must be a non-empty string' };
-		}
+	ScriptHandler.validateParameter = function validateParameter(parameter) {
+		for (var i = 0; i < ScriptUtils.PROPERTY_TYPES.length; ++i) {
+			var entry = ScriptUtils.PROPERTY_TYPES[i];
+			var propValue = parameter[entry.prop];
+			var isPropDefined = typeof propValue !== 'undefined';
 
-		// check for types
-		for (var i = 0; i < PROPERTY_VALIDATORS.length; i++) {
-			var entry = PROPERTY_VALIDATORS[i];
+			var msgStart = 'Property "' + entry.prop + '" must be ';
 
-			if (typeof parameter[entry.name] !== 'undefined') {
-				var maybeError = entry.validator(entry.name, parameter[entry.name]);
-				if (maybeError) {
-					return maybeError;
+			if (entry.mustBeDefined || isPropDefined) {
+				var validator = ScriptUtils.TYPE_VALIDATORS[entry.type];
+				var allowedValues = entry.getAllowedValues ? entry.getAllowedValues(parameter) : null;
+
+				if (isPropDefined && entry.minLength && propValue.length < entry.minLength) {
+					return { message: msgStart + 'longer than ' + (entry.minLength - 1) };
 				}
-			}
-		}
 
-		// check for type in a list of allowed types; must be defined
-		if (PARAMETER_TYPES.indexOf(parameter.type) === -1) {
-			return { message: 'Property "type" must be one of: ' + PARAMETER_TYPES.join(', ') };
-		}
+				if (allowedValues && allowedValues.indexOf(propValue) === -1) {
+					return { message: msgStart + 'one of: ' + allowedValues.join(', ') };
+				}
 
-		// check for controls in a list of controls; this depends on type
-		var allowedControls = TYPE_CONTROLS[parameter.type];
-		if (parameter.control !== undefined && allowedControls.indexOf(parameter.control) === -1) {
-			return { message: 'Property "control" must be one of: ' + allowedControls.join(', ') };
+				if (!validator(propValue)) {
+					return { message: msgStart + 'of type ' + entry.type };
+				}
+			}
 		}
 	};
 
@@ -703,7 +622,7 @@ define([
 	 * @param script
 	 * @param outScript
 	 */
-	ScriptHandler.validateParameters = function (script, outScript) {
+	ScriptHandler.validateParameters = function validateParameters(script, outScript) {
 		var errors = script.errors || [];
 		if (typeof script.externals !== 'object') {
 			outScript.externals = {};
@@ -780,4 +699,4 @@ define([
 	ScriptHandler.DOM_ID_PREFIX = '_script_';
 
 	return ScriptHandler;
-});
\ No newline at end of file
+});
diff --git a/src/goo/scripts/ScriptUtils.js b/src/goo/scripts/ScriptUtils.js
index e57bc211d..bfc7c21fd 100644
--- a/src/goo/scripts/ScriptUtils.js
+++ b/src/goo/scripts/ScriptUtils.js
@@ -7,7 +7,6 @@ define([
 
 	function ScriptUtils() {}
 
-
 	ScriptUtils.DEFAULTS_BY_TYPE = {
 		'float': 0,
 		'int': 0,
@@ -64,7 +63,9 @@ define([
 		};
 
 		return {
+			array: Array.isArray,
 			'float': _.isNumber,
+			'number': _.isNumber,
 			'string': _.isString,
 			'boolean': _.isBoolean,
 			'int': _.isInteger,
@@ -80,6 +81,82 @@ define([
 		};
 	})();
 
+	// The allowed types for the script parameters.
+	ScriptUtils.PARAMETER_TYPES = [
+		'string',
+		'int',
+		'float',
+		'vec2',
+		'vec3',
+		'vec4',
+		'boolean',
+		'texture',
+		'sound',
+		'camera',
+		'entity',
+		'animation'
+	];
+
+	// Specifies which controls can be used with each type.
+	ScriptUtils.PARAMETER_CONTROLS = (function () {
+		var typeControls = {
+			'string': ['key'],
+			'int': ['spinner', 'slider', 'jointSelector'],
+			'float': ['spinner', 'slider'],
+			'vec2': [],
+			'vec3': ['color'],
+			'vec4': ['color'],
+			'boolean': ['checkbox'],
+			'texture': [],
+			'image': [],
+			'sound': [],
+			'camera': [],
+			'entity': [],
+			'animation': []
+		};
+
+		// Add the controls that can be used with any type to the mapping of
+		// controls that ca be used for each type.
+		for (var type in typeControls) {
+			Array.prototype.push.apply(typeControls[type], ['dropdown', 'select']);
+		}
+
+		return typeControls;
+	})();
+
+	ScriptUtils.PROPERTY_TYPES = [
+		{
+			prop: 'key',
+			type: 'string',
+			mustBeDefined: true,
+			minLength: 1
+		},
+		{
+			prop: 'type',
+			type: 'string',
+			mustBeDefined: true,
+			minLength: 1,
+			getAllowedValues: function () {
+				return ScriptUtils.PARAMETER_TYPES;
+			}
+		},
+		{
+			prop: 'control',
+			type: 'string',
+			getAllowedValues: function (parameter) {
+				// Allowed controls depend on the parameter type.
+				return ScriptUtils.PARAMETER_CONTROLS[parameter.type];
+			}
+		},
+		{ prop: 'name', type: 'string' },
+		{ prop: 'min', type: 'number' },
+		{ prop: 'max', type: 'number' },
+		{ prop: 'scale', type: 'number' },
+		{ prop: 'decimals', type: 'number' },
+		{ prop: 'precision', type: 'number' },
+		{ prop: 'exponential', type: 'boolean' }
+	];
+
 	/**
 	 * Fill a passed parameters object with defaults from spec
 	 * @hidden
@@ -277,4 +354,4 @@ define([
 	};
 
 	return ScriptUtils;
-});
\ No newline at end of file
+});
diff --git a/test/unit/loaders/handlers/ScriptHandler-test.js b/test/unit/loaders/handlers/ScriptHandler-test.js
index a593a9e10..3ec44d243 100644
--- a/test/unit/loaders/handlers/ScriptHandler-test.js
+++ b/test/unit/loaders/handlers/ScriptHandler-test.js
@@ -30,17 +30,19 @@ define([
 			it('returns an error object if the key is missing or is a non-string', function () {
 				expect(validateParameter({
 					type: 'float'
-				})).toEqual({ message: 'Property "key" must be a non-empty string' });
+				})).toEqual({ message: 'Property "key" must be of type string' });
 
 				expect(validateParameter({
 					key: 123,
 					type: 'float'
-				})).toEqual({ message: 'Property "key" must be a non-empty string' });
+				})).toEqual({ message: 'Property "key" must be of type string' });
+			});
 
+			it('returns an error object if the key is an empty string', function () {
 				expect(validateParameter({
 					key: '',
 					type: 'float'
-				})).toEqual({ message: 'Property "key" must be a non-empty string' });
+				})).toEqual({ message: 'Property "key" must be longer than 0' });
 			});
 
 			it('returns an error object if the type is missing or bad', function () {