diff --git a/calc.html b/calc.html
index 8e396c9a..8434b28b 100644
--- a/calc.html
+++ b/calc.html
@@ -62,13 +62,13 @@
     <ul id="targets" class="targets"><li><button class="targetButton ui" title="Add new item." onclick="plusHandler()">+</a></li></ul>
 
     <div class="tabs">
-        <button class="tab_button" id="totals_button" onclick="clickTab('totals_tab')">Factory</button>
+        <button class="tab_button" id="totals_button" onclick="clickTab('totals')">Factory</button>
         <!--<button class="tab_button" id="steps_button" onclick="clickTab('steps_tab')">Items</button>-->
-        <button class="tab_button" id="graph_button" onclick="clickVisualize('graph_tab')">Visualize</button>
-        <button class="tab_button" id="settings_button" onclick="clickTab('settings_tab')">Settings</button>
-        <button class="tab_button" id="faq_button" onclick="clickTab('faq_tab')">FAQ</button>
-        <button class="tab_button" id="about_button" onclick="clickTab('about_tab')">About</button>
-        <button class="tab_button" id="debug_button" onclick="clickTab('debug_tab')">Debug</button>
+        <button class="tab_button" id="graph_button" onclick="clickVisualize('graph')">Visualize</button>
+        <button class="tab_button" id="settings_button" onclick="clickTab('settings')">Settings</button>
+        <button class="tab_button" id="faq_button" onclick="clickTab('faq')">FAQ</button>
+        <button class="tab_button" id="about_button" onclick="clickTab('about')">About</button>
+        <button class="tab_button" id="debug_button" onclick="clickTab('debug')">Debug</button>
     </div>
 
     <div id="steps_tab" class="tab">
diff --git a/display.js b/display.js
index fa7a6890..45e78e1b 100644
--- a/display.js
+++ b/display.js
@@ -900,9 +900,9 @@ function display() {
     }
     var totals = globalTotals
 
-    window.location.hash = "#" + formatSettings()
+    updateHash()
 
-    if (currentTab == "graph_tab") {
+    if (currentTab == "graph") {
         renderGraph(totals, spec.ignore)
     }
     recipeTable.displaySolution(totals)
diff --git a/events.js b/events.js
index 4d391ef8..e456bc59 100644
--- a/events.js
+++ b/events.js
@@ -1,5 +1,33 @@
 "use strict"
 
+// correctly handle back/forward buttons
+
+var plannedHashUpdate = false
+var navigationInProgress = false
+document.addEventListener("DOMContentLoaded", function() {
+    window.addEventListener("hashchange", function() {
+        if (plannedHashUpdate) {
+            // reset flag for next hashChange
+            plannedHashUpdate = false
+            return
+        }
+        navigationInProgress = true
+        var settings = loadSettings(window.location.hash)
+        if ("data" in settings && settings.data != currentMod()) {
+            document.getElementById("data_set").value = settings.data
+            changeMod(settings)
+        } else {
+            // changeMod >> loadData also does all this so don't repeat it
+            renderSettings(settings)
+            loadModules(settings)
+            loadItems(settings)
+            itemUpdate()
+        }
+        clickTab(settings.tab)
+        navigationInProgress = false
+    });
+});
+
 // build target events
 
 // The "+" button to add a new target.
@@ -48,11 +76,11 @@ function RateHandler(target) {
 
 // Obtains current data set from UI element, and resets the world with the new
 // data.
-function changeMod() {
+function changeMod(settings) {
     var modName = currentMod()
 
     reset()
-    loadData(modName)
+    loadData(modName, settings)
 }
 
 // Triggered when the display rate is changed.
@@ -306,22 +334,28 @@ function GraphClickHandler(node) {
 
 // tab events
 
-var DEFAULT_TAB = "totals_tab"
+var DEFAULT_TAB = "totals"
 
-var currentTab = DEFAULT_TAB
+var currentTab
 
 var tabMap = {
-    "totals_tab": "totals_button",
-    "steps_tab": "steps_button",
-    "graph_tab": "graph_button",
-    "settings_tab": "settings_button",
-    "about_tab": "about_button",
-    "faq_tab": "faq_button",
-    "debug_tab": "debug_button",
+    "totals": "totals_button",
+    "steps": "steps_button",
+    "graph": "graph_button",
+    "settings": "settings_button",
+    "about": "about_button",
+    "faq": "faq_button",
+    "debug": "debug_button",
 }
 
 // Triggered when a tab is clicked on.
 function clickTab(tabName) {
+    if (!tabName) {
+        tabName = DEFAULT_TAB
+    }
+    if (tabName == currentTab) {
+        return
+    }
     currentTab = tabName
     var tabs = document.getElementsByClassName("tab")
     for (var i=0; i < tabs.length; i++) {
@@ -332,18 +366,15 @@ function clickTab(tabName) {
     for (var i=0; i < buttons.length; i++) {
         buttons[i].classList.remove("active")
     }
-
-    document.getElementById(tabName).style.display = "block"
+    document.getElementById(tabName + "_tab").style.display = "block"
     var button = document.getElementById(tabMap[tabName])
     button.classList.add("active")
-    if (initDone) {
-        window.location.hash = "#" + formatSettings()
-    }
+    updateHash()
 }
 
 // Triggered when the "Visualize" tab is clicked on.
-function clickVisualize(event, tabName) {
-    clickTab(event, tabName)
+function clickVisualize(tabName) {
+    clickTab(tabName)
     renderGraph(globalTotals, spec.ignore)
 }
 
@@ -357,4 +388,3 @@ function toggleVisible(targetID) {
         target.style.display = "none"
     }
 }
-
diff --git a/fragment.js b/fragment.js
index 0ad1a4a4..339c38fb 100644
--- a/fragment.js
+++ b/fragment.js
@@ -1,9 +1,13 @@
 "use strict"
 
-function formatSettings() {
+function updateHash() {
+    if (navigationInProgress) {
+        return
+    }
+
     var settings = ""
     if (currentTab != DEFAULT_TAB) {
-        settings += "tab=" + currentTab.slice(0, currentTab.indexOf("_")) + "&"
+        settings += "tab=" + currentTab + "&"
     }
     var mod = currentMod()
     if (mod != DEFAULT_MODIFICATION) {
@@ -110,9 +114,13 @@ function formatSettings() {
     }
     var zip = "zip=" + window.btoa(pako.deflateRaw(settings, {to: "string"}))
     if (zip.length < settings.length) {
-        return zip
+        settings = zip
+    }
+    settings = "#" + settings
+    if (window.location.hash != settings) {
+        plannedHashUpdate = true;
+        window.location.hash = settings
     }
-    return settings
 }
 
 function loadSettings(fragment) {
diff --git a/init.js b/init.js
index 3043c543..117ab80c 100644
--- a/init.js
+++ b/init.js
@@ -18,8 +18,6 @@ var shortModules
 // Array of item groups, in turn divided into subgroups. For display purposes.
 var itemGroups
 
-var initDone = false
-
 // Set the page back to a state immediately following initial setup, but before
 // the dataset is loaded for the first time.
 //
@@ -48,6 +46,80 @@ function reset() {
     oldTotals.parentNode.replaceChild(newTotals, oldTotals)
 }
 
+function loadItems(settings) {
+    // clear current targets
+    build_targets = []
+    var targetList = document.getElementById("targets")
+    targetList.innerHTML = targetList.lastChild.outerHTML
+
+    if ("items" in settings && settings.items != "") {
+        var targets = settings.items.split(",")
+        for (var i=0; i < targets.length; i++) {
+            var targetString = targets[i]
+            var parts = targetString.split(":")
+            var name = parts[0]
+            var target = addTarget(name)
+            var type = parts[1]
+            if (type == "f") {
+                target.setFactories(parts[2])
+            } else if (type == "r") {
+                target.setRate(parts[2])
+            } else {
+                throw new Error("unknown target type")
+            }
+        }
+    } else {
+        addTarget()
+    }
+}
+
+function loadModules(settings) {
+    if ("modules" in settings && settings.modules != "") {
+        var moduleSettings = settings.modules.split(",")
+        for (var i=0; i < moduleSettings.length; i++) {
+            var bothSettings = moduleSettings[i].split(";")
+            var factoryModuleSettings = bothSettings[0]
+            var beaconSettings = bothSettings[1]
+
+            var singleModuleSettings = factoryModuleSettings.split(":")
+            var recipeName = singleModuleSettings[0]
+            var recipe = solver.recipes[recipeName]
+            var moduleNameList = singleModuleSettings.slice(1)
+            for (var j=0; j < moduleNameList.length; j++) {
+                var moduleName = moduleNameList[j]
+                if (moduleName && moduleName != "null") {
+                    var module
+                    if (moduleName in modules) {
+                        module = modules[moduleName]
+                    } else if (moduleName in shortModules) {
+                        module = shortModules[moduleName]
+                    }
+                    if (module) {
+                        spec.setModule(recipe, j, module)
+                    }
+                }
+            }
+            if (beaconSettings) {
+                beaconSettings = beaconSettings.split(":")
+                var moduleName = beaconSettings[0]
+                var module = null
+                if (moduleName in modules) {
+                    module = modules[moduleName]
+                } else if (moduleName in shortModules) {
+                    module = shortModules[moduleName]
+                }
+                var factory = spec.getFactory(recipe)
+                var count = RationalFromFloat(Number(beaconSettings[1]))
+                if (module === spec.defaultBeacon) {
+                    module = null
+                }
+                factory.beaconModule = module
+                factory.beaconCount = count
+            }
+        }
+    }
+}
+
 function loadDataRunner(modName, callback) {
     var xobj = new XMLHttpRequest()
     var mod = MODIFICATIONS[modName]
@@ -96,71 +168,9 @@ function loadData(modName, settings) {
         solver = new Solver(items, recipes)
 
         renderSettings(settings)
-
-        if ("items" in settings && settings.items != "") {
-            var targets = settings.items.split(",")
-            for (var i=0; i < targets.length; i++) {
-                var targetString = targets[i]
-                var parts = targetString.split(":")
-                var name = parts[0]
-                var target = addTarget(name)
-                var type = parts[1]
-                if (type == "f") {
-                    target.setFactories(parts[2])
-                } else if (type == "r") {
-                    target.setRate(parts[2])
-                } else {
-                    throw new Error("unknown target type")
-                }
-            }
-        } else {
-            addTarget()
-        }
-        if ("modules" in settings && settings.modules != "") {
-            var moduleSettings = settings.modules.split(",")
-            for (var i=0; i < moduleSettings.length; i++) {
-                var bothSettings = moduleSettings[i].split(";")
-                var factoryModuleSettings = bothSettings[0]
-                var beaconSettings = bothSettings[1]
-
-                var singleModuleSettings = factoryModuleSettings.split(":")
-                var recipeName = singleModuleSettings[0]
-                var recipe = recipes[recipeName]
-                var moduleNameList = singleModuleSettings.slice(1)
-                for (var j=0; j < moduleNameList.length; j++) {
-                    var moduleName = moduleNameList[j]
-                    if (moduleName && moduleName != "null") {
-                        var module
-                        if (moduleName in modules) {
-                            module = modules[moduleName]
-                        } else if (moduleName in shortModules) {
-                            module = shortModules[moduleName]
-                        }
-                        if (module) {
-                            spec.setModule(recipe, j, module)
-                        }
-                    }
-                }
-                if (beaconSettings) {
-                    beaconSettings = beaconSettings.split(":")
-                    var moduleName = beaconSettings[0]
-                    var module = null
-                    if (moduleName in modules) {
-                        module = modules[moduleName]
-                    } else if (moduleName in shortModules) {
-                        module = shortModules[moduleName]
-                    }
-                    var factory = spec.getFactory(recipe)
-                    var count = RationalFromFloat(Number(beaconSettings[1]))
-                    if (module === spec.defaultBeacon) {
-                        module = null
-                    }
-                    factory.beaconModule = module
-                    factory.beaconCount = count
-                }
-            }
-        }
-        initDone = true
+        loadModules(settings)
+        loadItems(settings)
+        clickTab(settings.tab)
         itemUpdate()
     })
 }
@@ -168,11 +178,5 @@ function loadData(modName, settings) {
 function init() {
     var settings = loadSettings(window.location.hash)
     renderDataSetOptions(settings)
-    if ("tab" in settings) {
-        currentTab = settings.tab + "_tab"
-    }
     loadData(currentMod(), settings)
-    // We don't need to call clickVisualize here, as we will properly render
-    // the graph when we call itemUpdate() at the end of initialization.
-    clickTab(currentTab)
 }