diff --git a/README.md b/README.md
index 33d9944..9c6f18a 100644
--- a/README.md
+++ b/README.md
@@ -7,18 +7,25 @@ A JavaScript plugin to contain an element within its parent element.
 * Pure JavaScript with no dependencies
 * Configures the horizontal and vertical alignment of the contained element
 * Can detect the native size or have it specified at runtime
+* Includes function to update the size and position
 
 ## Usage
 
 ```
 window.onload = function() {
-    containElement({
+    var contain = new ContainElement({
         id: 'element', // the id of the element to be contained
         width: '100', // (optional) element width in pixels (unset: element width)
         height: '100', // (optional) element height in pixels (unset: element height)
         valign: 'top', // (optional) vertical alignment: top|bottom (unset: middle)
         halign: 'left' // (optional) horizontal alignment: left|right (unset: middle)
     });
+
+    // (example) update the size and positioning on window resize
+    window.onresize = function(event) { contain.update(); };
+
+    // (example) update the size and positioning on orientation change
+    screen.addEventListener('orientationchange', function() { contain.update(); });
 };
 ```
 
diff --git a/contain-element.js b/contain-element.js
index 1af648e..ccc8c7a 100644
--- a/contain-element.js
+++ b/contain-element.js
@@ -1,4 +1,4 @@
-function containElement(options) {
+function ContainElement(options) {
 	var scaleFactor = 1;
 	var element = document.getElementById(options.id);
 	var elementWidth = options.width || element.offsetWidth;
@@ -12,7 +12,7 @@ function containElement(options) {
 	if (element.parentElement.style.position != 'relative' && element.parentElement.style.position != 'absolute' && element.parentElement.style.position != 'fixed')
 		element.parentElement.style.position = 'relative';
 
-	function scaleElement() {
+	function updateContain() {
 		var parentWidth = element.parentElement.offsetWidth;
 		var parentHeight = element.parentElement.offsetHeight;
 
@@ -67,13 +67,14 @@ function containElement(options) {
 			}
 		} else {
 			// Try again in 30ms if the document didn't load enough to determine its width and height yet
-			window.setTimeout(scaleElement, 30);
+			window.setTimeout(updateContain, 30);
 		}
 	}
 
 	// Run the scale function and bind it to various window-size-changing events
-	scaleElement();
-	window.onresize = function(event) { scaleElement(); };
-	screen.addEventListener('orientationchange', function() { scaleElement(); });
+	updateContain();
+
+	// Add scale function to the library
+	this.update = function() { updateContain(); };
 }