Update script.js

script.js

@@ -5,10 +5,24 @@ let seekTime = 0;
 let direction = 1; // 1 for right, -1 for left
 let animationInterval;
 
+document.addEventListener("DOMContentLoaded", function () {
+    initialize();
+});
+
 function initialize() {
     head = document.getElementById("head");
     const diskTrack = document.getElementById("diskTrack");
-    updateTrackElements(diskTrack);
+
+    if (!head || !diskTrack) {
+        console.error("Required elements not found");
+        return;
+    }
+
+    try {
+        updateTrackElements(diskTrack);
+    } catch (error) {
+        console.error("Error initializing track elements:", error);
+    }
 }
 
 function updateTrackElements(diskTrack) {
@@ -47,164 +61,193 @@ function resetButtonStates() {
 }
 
 function startFCFS() {
-    reset();
-    resetButtonStates();
-    document
-        .querySelector('button[onclick="startFCFS()"]')
-        .classList.add("active");
-    const diskTrack = document.getElementById("diskTrack");
-    let currentPosition = parseInt(
-        document.getElementById("initialHead").value
-    );
-    let currentRequestIndex = 0;
-
-    animationInterval = setInterval(() => {
-        if (currentRequestIndex >= requests.length) {
+    try {
+        if (animationInterval) {
             clearInterval(animationInterval);
-            return;
         }
+        reset();
+        resetButtonStates();
+        document
+            .querySelector('button[onclick="startFCFS()"]')
+            .classList.add("active");
+        const diskTrack = document.getElementById("diskTrack");
+        let currentPosition = parseInt(
+            document.getElementById("initialHead").value
+        );
+        let currentRequestIndex = 0;
 
-        const trackWidth = diskTrack.offsetWidth;
-        const targetPosition = requests[currentRequestIndex];
-        const targetPixel = (targetPosition / 199) * trackWidth;
+        animationInterval = setInterval(() => {
+            if (currentRequestIndex >= requests.length) {
+                clearInterval(animationInterval);
+                return;
+            }
 
-        seekTime += Math.abs(targetPosition - currentPosition);
-        currentPosition = targetPosition;
+            const trackWidth = diskTrack.offsetWidth;
+            const targetPosition = requests[currentRequestIndex];
+            const targetPixel = (targetPosition / 199) * trackWidth;
 
-        head.style.left = targetPixel + "px";
+            seekTime += Math.abs(targetPosition - currentPosition);
+            currentPosition = targetPosition;
 
-        setTimeout(() => {
-            const requestElements = document.querySelectorAll(".request");
-            requestElements.forEach((req) => {
-                const reqPos = Math.round(
-                    (parseFloat(req.style.left) / trackWidth) * 199
-                );
-                if (reqPos === targetPosition) {
-                    req.classList.add("served");
-                }
-            });
-        }, 400);
+            head.style.left = targetPixel + "px";
 
-        direction = currentPosition > targetPosition ? -1 : 1;
-        updateStats(targetPosition);
-        currentRequestIndex++;
-    }, 1000);
+            setTimeout(() => {
+                const requestElements = document.querySelectorAll(".request");
+                requestElements.forEach((req) => {
+                    const reqPos = Math.round(
+                        (parseFloat(req.style.left) / trackWidth) * 199
+                    );
+                    if (reqPos === targetPosition) {
+                        req.classList.add("served");
+                    }
+                });
+            }, 400);
+
+            direction = currentPosition > targetPosition ? -1 : 1;
+            updateStats(targetPosition);
+            currentRequestIndex++;
+        }, 1000);
+    } catch (error) {
+        console.error("Error in FCFS:", error);
+    }
 }
 
 function startSSTF() {
-    reset();
-    resetButtonStates();
-    document
-        .querySelector('button[onclick="startSSTF()"]')
-        .classList.add("active");
-    const diskTrack = document.getElementById("diskTrack");
-    const trackWidth = diskTrack.offsetWidth;
-    const initialHead = parseInt(document.getElementById("initialHead").value);
-    let currentPosition = initialHead;
-    let remainingRequests = [...requests];
-
-    animationInterval = setInterval(() => {
-        if (remainingRequests.length === 0) {
+    try {
+        if (animationInterval) {
             clearInterval(animationInterval);
-            return;
         }
-
-        let closestRequest = remainingRequests.reduce((closest, current) => {
-            let closestDistance = Math.abs(closest - currentPosition);
-            let currentDistance = Math.abs(current - currentPosition);
-            return currentDistance < closestDistance ? current : closest;
-        });
-
-        remainingRequests = remainingRequests.filter(
-            (req) => req !== closestRequest
+        reset();
+        resetButtonStates();
+        document
+            .querySelector('button[onclick="startSSTF()"]')
+            .classList.add("active");
+        const diskTrack = document.getElementById("diskTrack");
+        const trackWidth = diskTrack.offsetWidth;
+        const initialHead = parseInt(
+            document.getElementById("initialHead").value
         );
-        const targetPixel = (closestRequest / 199) * trackWidth;
+        let currentPosition = initialHead;
+        let remainingRequests = [...requests];
 
-        seekTime += Math.abs(closestRequest - currentPosition);
-        currentPosition = closestRequest;
+        animationInterval = setInterval(() => {
+            if (remainingRequests.length === 0) {
+                clearInterval(animationInterval);
+                return;
+            }
 
-        head.style.left = targetPixel + "px";
-
-        setTimeout(() => {
-            const requests = document.querySelectorAll(".request");
-            requests.forEach((req) => {
-                const reqPos = Math.round(
-                    (parseFloat(req.style.left) / trackWidth) * 199
-                );
-                if (reqPos === closestRequest) {
-                    req.classList.add("served");
+            let closestRequest = remainingRequests.reduce(
+                (closest, current) => {
+                    let closestDistance = Math.abs(closest - currentPosition);
+                    let currentDistance = Math.abs(current - currentPosition);
+                    return currentDistance < closestDistance
+                        ? current
+                        : closest;
                 }
-            });
-        }, 400);
+            );
 
-        direction = currentPosition > closestRequest ? -1 : 1;
-        updateStats(closestRequest);
-    }, 1000);
+            remainingRequests = remainingRequests.filter(
+                (req) => req !== closestRequest
+            );
+            const targetPixel = (closestRequest / 199) * trackWidth;
+
+            seekTime += Math.abs(closestRequest - currentPosition);
+            currentPosition = closestRequest;
+
+            head.style.left = targetPixel + "px";
+
+            setTimeout(() => {
+                const requests = document.querySelectorAll(".request");
+                requests.forEach((req) => {
+                    const reqPos = Math.round(
+                        (parseFloat(req.style.left) / trackWidth) * 199
+                    );
+                    if (reqPos === closestRequest) {
+                        req.classList.add("served");
+                    }
+                });
+            }, 400);
+
+            direction = currentPosition > closestRequest ? -1 : 1;
+            updateStats(closestRequest);
+        }, 1000);
+    } catch (error) {
+        console.error("Error in SSTF:", error);
+    }
 }
 
 function startSCAN() {
-    reset();
-    resetButtonStates();
-    document
-        .querySelector('button[onclick="startSCAN()"]')
-        .classList.add("active");
-    const diskTrack = document.getElementById("diskTrack");
-    const trackWidth = diskTrack.offsetWidth;
-    const initialHead = parseInt(document.getElementById("initialHead").value);
-    const initialDirection = document.getElementById("scanDirection").value;
-    let currentPosition = initialHead;
-
-    let sortedRequests = [...requests].sort((a, b) => a - b);
-    let headIndex = sortedRequests.findIndex((x) => x >= initialHead);
-
-    if (headIndex === -1) headIndex = sortedRequests.length;
-
-    let scanOrder;
-    if (initialDirection === "right") {
-        scanOrder = [
-            ...sortedRequests.slice(headIndex),
-            ...sortedRequests.slice(0, headIndex).reverse(),
-        ];
-        direction = 1;
-    } else {
-        scanOrder = [
-            ...sortedRequests.slice(0, headIndex).reverse(),
-            ...sortedRequests.slice(headIndex),
-        ];
-        direction = -1;
-    }
-
-    let currentRequestIndex = 0;
-
-    animationInterval = setInterval(() => {
-        if (currentRequestIndex >= scanOrder.length) {
+    try {
+        if (animationInterval) {
             clearInterval(animationInterval);
-            return;
+        }
+        reset();
+        resetButtonStates();
+        document
+            .querySelector('button[onclick="startSCAN()"]')
+            .classList.add("active");
+        const diskTrack = document.getElementById("diskTrack");
+        const trackWidth = diskTrack.offsetWidth;
+        const initialHead = parseInt(
+            document.getElementById("initialHead").value
+        );
+        const initialDirection = document.getElementById("scanDirection").value;
+        let currentPosition = initialHead;
+
+        let sortedRequests = [...requests].sort((a, b) => a - b);
+        let headIndex = sortedRequests.findIndex((x) => x >= initialHead);
+
+        if (headIndex === -1) headIndex = sortedRequests.length;
+
+        let scanOrder;
+        if (initialDirection === "right") {
+            scanOrder = [
+                ...sortedRequests.slice(headIndex),
+                ...sortedRequests.slice(0, headIndex).reverse(),
+            ];
+            direction = 1;
+        } else {
+            scanOrder = [
+                ...sortedRequests.slice(0, headIndex).reverse(),
+                ...sortedRequests.slice(headIndex),
+            ];
+            direction = -1;
         }
 
-        const targetPosition = scanOrder[currentRequestIndex];
-        const targetPixel = (targetPosition / 199) * trackWidth;
+        let currentRequestIndex = 0;
 
-        seekTime += Math.abs(targetPosition - currentPosition);
-        currentPosition = targetPosition;
+        animationInterval = setInterval(() => {
+            if (currentRequestIndex >= scanOrder.length) {
+                clearInterval(animationInterval);
+                return;
+            }
 
-        head.style.left = targetPixel + "px";
+            const targetPosition = scanOrder[currentRequestIndex];
+            const targetPixel = (targetPosition / 199) * trackWidth;
 
-        setTimeout(() => {
-            const requests = document.querySelectorAll(".request");
-            requests.forEach((req) => {
-                const reqPos = Math.round(
-                    (parseFloat(req.style.left) / trackWidth) * 199
-                );
-                if (reqPos === targetPosition) {
-                    req.classList.add("served");
-                }
-            });
-        }, 400);
+            seekTime += Math.abs(targetPosition - currentPosition);
+            currentPosition = targetPosition;
 
-        updateStats(targetPosition);
-        currentRequestIndex++;
-    }, 1000);
+            head.style.left = targetPixel + "px";
+
+            setTimeout(() => {
+                const requests = document.querySelectorAll(".request");
+                requests.forEach((req) => {
+                    const reqPos = Math.round(
+                        (parseFloat(req.style.left) / trackWidth) * 199
+                    );
+                    if (reqPos === targetPosition) {
+                        req.classList.add("served");
+                    }
+                });
+            }, 400);
+
+            updateStats(targetPosition);
+            currentRequestIndex++;
+        }, 1000);
+    } catch (error) {
+        console.error("Error in SCAN:", error);
+    }
 }
 
 function reset() {