diff --git a/background.js b/background.js
index 86da312d..a0a7e8e6 100644
--- a/background.js
+++ b/background.js
@@ -89,7 +89,7 @@ function getStyles(options, callback) {
 					}
 					var metaValue = values.metaValue;
 					if (currentStyle == null || currentStyle.id != values.id) {
-						currentStyle = {id: values.id, url: values.url, updateUrl: values.updateUrl, md5Url: values.md5Url, name: values.name, enabled: values.enabled, sections: []};
+						currentStyle = {id: values.id, url: values.url, updateUrl: values.updateUrl, md5Url: values.md5Url, name: values.name, enabled: values.enabled, originalMd5: values.originalMd5, sections: []};
 						cachedStyles.push(currentStyle);
 					}
 					if (currentSection == null || currentSection.id != values.section_id) {
@@ -199,15 +199,18 @@ function saveStyle(o, callback) {
 				if ("md5Url" in o) {
 					t.executeSql('UPDATE styles SET md5Url = ? WHERE id = ?;', [o.md5Url, o.id]);
 				}
+				if ("originalMd5" in o) {
+					t.executeSql('UPDATE styles SET originalMd5 = ? WHERE id = ?;', [o.originalMd5, o.id]);
+				}
 			} else {
 				// create a new record
 				// set optional things to null if they're undefined
-				["updateUrl", "md5Url", "url"].filter(function(att) {
+				["updateUrl", "md5Url", "url", "originalMd5"].filter(function(att) {
 					return !(att in o);
 				}).forEach(function(att) {
 					o[att] = null;
 				});
-				t.executeSql('INSERT INTO styles (name, enabled, url, updateUrl, md5Url) VALUES (?, ?, ?, ?, ?);', [o.name, true, o.url, o.updateUrl, o.md5Url]);
+				t.executeSql('INSERT INTO styles (name, enabled, url, updateUrl, md5Url, originalMd5) VALUES (?, ?, ?, ?, ?, ?);', [o.name, true, o.url, o.updateUrl, o.md5Url, o.originalMd5]);
 			}
 
 			if ("sections" in o) {
diff --git a/install.js b/install.js
index e82460c0..7ae67499 100644
--- a/install.js
+++ b/install.js
@@ -4,25 +4,37 @@ chrome.extension.sendMessage({method: "getStyles", url: getMeta("stylish-id-url"
 	} else {
 		var installedStyle = response[0];
 		// maybe an update is needed
-		getResource(getMeta("stylish-code-chrome"), function(code) {
-			// this would indicate a failure (a style with settings?).
-			if (code == null) {
-				sendEvent("styleCanBeUpdatedChrome");
-			}
-			var json = JSON.parse(code);
-			if (json.sections.length == installedStyle.sections.length) {
-				if (json.sections.every(function(section) {
-					return installedStyle.sections.some(function(installedSection) {
-						return sectionsAreEqual(section, installedSection);
-					});
-				})) {
-					// everything's the same
-					sendEvent("styleAlreadyInstalledChrome");
-					return;
-				};
-			}
-			sendEvent("styleCanBeUpdatedChrome");
-		});
+		// use the md5 if available
+		var md5Url = getMeta("stylish-md5-url");
+		if (md5Url && installedStyle.md5Url && installedStyle.originalMd5) {
+			getResource(md5Url, function(md5) {
+				if (md5 == installedStyle.originalMd5) {
+					sendEvent("styleAlreadyInstalledChrome", {updateUrl: installedStyle.updateUrl});
+				} else {
+					sendEvent("styleCanBeUpdatedChrome", {updateUrl: installedStyle.updateUrl});
+				}
+			});
+		} else {
+			getResource(getMeta("stylish-code-chrome"), function(code) {
+				// this would indicate a failure (a style with settings?).
+				if (code == null) {
+					sendEvent("styleCanBeUpdatedChrome", {updateUrl: installedStyle.updateUrl});
+				}
+				var json = JSON.parse(code);
+				if (json.sections.length == installedStyle.sections.length) {
+					if (json.sections.every(function(section) {
+						return installedStyle.sections.some(function(installedSection) {
+							return sectionsAreEqual(section, installedSection);
+						});
+					})) {
+						// everything's the same
+						sendEvent("styleAlreadyInstalledChrome", {updateUrl: installedStyle.updateUrl});
+						return;
+					};
+				}
+				sendEvent("styleCanBeUpdatedChrome", {updateUrl: installedStyle.updateUrl});
+			});
+		}
 	}
 });
 
@@ -49,9 +61,11 @@ function arraysAreEqual(a, b) {
 	});
 }
 
-function sendEvent(type) {
-	var stylishEvent = document.createEvent("Events");
-	stylishEvent.initEvent(type, false, false, document.defaultView, null);
+function sendEvent(type, data) {
+	if (typeof data == "undefined") {
+		data = null;
+	}
+	var stylishEvent = new CustomEvent(type, {detail: data});
 	document.dispatchEvent(stylishEvent);
 }
 
@@ -77,7 +91,9 @@ document.addEventListener("stylishUpdateChrome", function() {
 		if (confirm(chrome.i18n.getMessage('styleUpdate', [style.name]))) {
 			getResource(getMeta("stylish-code-chrome"), function(code) {
 				var json = JSON.parse(code);
-				chrome.extension.sendMessage({method: "saveStyle", id: style.id, sections: json.sections}, function() {
+				json.method = "saveStyle";
+				json.id = style.id;
+				chrome.extension.sendMessage(json, function() {
 					sendEvent("styleInstalledChrome");
 				});
 			});
diff --git a/manage.js b/manage.js
index 3d7c2d08..ccdd9e3e 100644
--- a/manage.js
+++ b/manage.js
@@ -1,6 +1,8 @@
 var styleTemplate = document.createElement("div");
 styleTemplate.innerHTML = "<h2 class='style-name'></h2><p class='applies-to'></p><p class='actions'><a class='style-edit-link' href='edit.html?id='><button>" + t('editStyleLabel') + "</button></a><button class='enable'>" + t('enableStyleLabel') + "</button><button class='disable'>" + t('disableStyleLabel') + "</button><button class='delete'>" + t('deleteStyleLabel') + "</button><button class='check-update'>" + t('checkForUpdate') + "</button><button class='update'>" + t('installUpdate') + "</button><span class='update-note'></span></p>";
 
+var lastUpdatedStyleId = null;
+
 var appliesToExtraTemplate = document.createElement("span");
 appliesToExtraTemplate.className = "applies-to-extra";
 appliesToExtraTemplate.innerHTML = " " + t('appliesDisplayTruncatedSuffix');
@@ -21,6 +23,12 @@ function createStyleElement(style) {
 	if (style.updateUrl) {
 		e.setAttribute("style-update-url", style.updateUrl);
 	}
+	if (style.md5Url) {
+		e.setAttribute("style-md5-url", style.md5Url);
+	}
+	if (style.originalMd5) {
+		e.setAttribute("style-original-md5", style.originalMd5);
+	}
 	
 	var styleName = e.querySelector(".style-name");
 	styleName.appendChild(document.createTextNode(style.name));
@@ -131,7 +139,13 @@ chrome.extension.onMessage.addListener(function(request, sender, sendResponse) {
 
 function handleUpdate(style) {
 	var installed = document.getElementById("installed");
-	installed.replaceChild(createStyleElement(style), installed.querySelector("[style-id='" + style.id + "']"));
+	var element = createStyleElement(style);
+	installed.replaceChild(element, installed.querySelector("[style-id='" + style.id + "']"));
+	if (style.id == lastUpdatedStyleId) {
+		lastUpdatedStyleId = null;
+		element.className = element.className += " update-done";
+		element.querySelector(".update-note").innerHTML = t('updateCompleted');
+	};
 }
 
 function handleDelete(id) {
@@ -152,31 +166,78 @@ function checkUpdate(element) {
 	element.className = element.className.replace("checking-update", "").replace("no-update", "").replace("can-update", "") + " checking-update";
 	var id = element.getAttribute("style-id");
 	var url = element.getAttribute("style-update-url");
+	var md5Url = element.getAttribute("style-md5-url");
+	var originalMd5 = element.getAttribute("style-original-md5");
+
+	function handleSuccess(forceUpdate, serverJson) {
+		chrome.extension.sendMessage({method: "getStyles", id: id}, function(styles) {
+			var style = styles[0];
+			if (!forceUpdate && codeIsEqual(style.sections, serverJson.sections)) {
+				handleNeedsUpdate("no", id, serverJson);
+			} else {
+				handleNeedsUpdate("yes", id, serverJson);
+			}
+		});
+	}
+
+	function handleFailure(status) {
+		if (status == 0) {
+			handleNeedsUpdate(t('updateCheckFailServerUnreachable'), id, null);
+		} else {
+			handleNeedsUpdate(t('updateCheckFailBadResponseCode', [status]), id, null);
+		}
+	}
+
+	if (!md5Url || !originalMd5) {
+		checkUpdateFullCode(url, false, handleSuccess, handleFailure)
+	} else {
+		checkUpdateMd5(originalMd5, md5Url, function(needsUpdate) {
+			if (needsUpdate) {
+				// If the md5 shows a change we will update regardless of whether the code looks different
+				checkUpdateFullCode(url, true, handleSuccess, handleFailure);
+			} else {
+				handleNeedsUpdate("no", id, null);
+			}
+		}, handleFailure);
+	}
+}
+
+function checkUpdateFullCode(url, forceUpdate, successCallback, failureCallback) {
+	download(url, function(responseText) {
+		successCallback(forceUpdate, JSON.parse(responseText));
+	}, failureCallback);
+}
+
+function checkUpdateMd5(originalMd5, md5Url, successCallback, failureCallback) {
+	download(md5Url, function(responseText) {
+		if (responseText.length != 32) {
+			failureCallback(-1);
+			return;
+		}
+		successCallback(responseText != originalMd5);
+	}, failureCallback);
+}
+
+function download(url, successCallback, failureCallback) {
 	var xhr = new XMLHttpRequest();
-	xhr.open("GET", url, true);	
 	xhr.onreadystatechange = function (aEvt) {  
 		if (xhr.readyState == 4) {  
 			if (xhr.status == 200) {
-				checkNeedsUpdate(id, JSON.parse(xhr.responseText));
-			} else if (xhr.status == 0) {
-				handleNeedsUpdate(t('updateCheckFailServerUnreachable'), id, null);
+				successCallback(xhr.responseText)
 			} else {
-				handleNeedsUpdate(t('updateCheckFailBadResponseCode', [xhr.status]), id, null);
+				failureCallback(xhr.status);
 			}
 		}
-	};  
-	xhr.send(null);
-}
-
-function checkNeedsUpdate(id, serverJson) {
-	chrome.extension.sendMessage({method: "getStyles", id: id}, function(styles) {
-		var style = styles[0];
-		if (codeIsEqual(style.sections, serverJson.sections)) {
-			handleNeedsUpdate("no", id, serverJson);
-		} else {
-			handleNeedsUpdate("yes", id, serverJson);
-		}
-	});
+	}
+	if (url.length > 2000) {
+		var parts = url.split("?");
+		xhr.open("POST", parts[0], true);
+		xhr.setRequestHeader("Content-type","application/x-www-form-urlencoded");
+		xhr.send(parts[1]);
+	} else {
+		xhr.open("GET", url, true);
+		xhr.send();
+	}
 }
 
 function handleNeedsUpdate(needsUpdate, id, serverJson) {
@@ -200,11 +261,16 @@ function handleNeedsUpdate(needsUpdate, id, serverJson) {
 
 function doUpdate(event) {
 	var element = getStyleElement(event);
-	chrome.extension.sendMessage({method: "saveStyle", id: element.getAttribute('style-id'), sections: element.updatedCode.sections}, function() {
-		element.updatedCode = "";
-		element.className = element.className.replace("can-update", "update-done");
-		element.querySelector(".update-note").innerHTML = t('updateCompleted');
-	});
+
+	var updatedCode = element.updatedCode;
+	// update everything but name
+	delete updatedCode.name;
+	updatedCode.id = element.getAttribute('style-id');
+	updatedCode.method = "saveStyle";
+
+	// updating the UI will be handled by the general update listener
+	lastUpdatedStyleId = updatedCode.id;
+	chrome.extension.sendMessage(updatedCode);
 }
 
 function codeIsEqual(a, b) {
diff --git a/storage.js b/storage.js
index 3bee18b3..f729ad45 100644
--- a/storage.js
+++ b/storage.js
@@ -18,6 +18,8 @@ function getDatabase(ready, error) {
 		dbV13(stylishDb, error, ready);
 	} else if (stylishDb.version == "1.3") {
 		dbV14(stylishDb, error, ready);
+	} else if (stylishDb.version == "1.4") {
+		dbV15(stylishDb, error, ready);
 	} else {
 	  ready(stylishDb);
 	}
@@ -64,6 +66,12 @@ function dbV14(d, error, done) {
 	}, error, function() { done(d)});
 }
 
+function dbV15(d, error, done) {
+	d.changeVersion(d.version, '1.5', function (t) {
+		t.executeSql('ALTER TABLE styles ADD COLUMN originalMd5 TEXT NULL;');
+	}, error, function() { done(d)});
+}
+
 function enableStyle(id, enabled) {
 	getDatabase(function(db) {
 		db.transaction(function (t) {