Better type-based checking on old and new values

Renderer.js

@@ -260,7 +260,11 @@
 		if (newValue == null || (element.type === 'number' && isNaN(newValue))) {
 			newValue = ''
 		}
-		if (element[this.name] != newValue) {
+		var oldValue = element[this.name]
+		if (typeof oldValue === 'string' && typeof newValue !== 'string') {
+			newValue = newValue == null ? '' : String(newValue)
+		}
+		if (oldValue != newValue) {
 			element[this.name] = newValue
 		}
 	}

tests/Element.js

@@ -135,6 +135,12 @@ define([
 			})
 			assert.strictEqual(new Radio().type, 'radio')
 		},
+		numberInput0: function() {
+			var numberInput = new NumberInput(new Variable(0))
+			document.body.appendChild(numberInput)
+			assert.strictEqual(numberInput.type, 'number')
+			assert.strictEqual(numberInput.valueAsNumber, 0)
+		},
 		dateInput: function() {
 			var startingDate = new Date(1458345600000)
 			var dateVariable = new Variable(startingDate)