diff --git a/solution/0800-0899/0840.Magic Squares In Grid/README.md b/solution/0800-0899/0840.Magic Squares In Grid/README.md
index 338eb194fb833..2e9b56973f791 100644
--- a/solution/0800-0899/0840.Magic Squares In Grid/README.md	
+++ b/solution/0800-0899/0840.Magic Squares In Grid/README.md	
@@ -318,6 +318,158 @@ function numMagicSquaresInside(grid: number[][]): number {
 }
 ```
 
+#### JavaScript
+
+```js
+function numMagicSquaresInside(grid) {
+    const m = grid.length;
+    const n = grid[0].length;
+    const check = (i, j) => {
+        if (i + 3 > m || j + 3 > n) {
+            return 0;
+        }
+        const cnt = Array(16).fill(0);
+        const row = Array(3).fill(0);
+        const col = Array(3).fill(0);
+        let [a, b] = [0, 0];
+        for (let x = i; x < i + 3; ++x) {
+            for (let y = j; y < j + 3; ++y) {
+                const v = grid[x][y];
+                if (v < 1 || v > 9 || ++cnt[v] > 1) {
+                    return 0;
+                }
+                row[x - i] += v;
+                col[y - j] += v;
+                if (x - i === y - j) {
+                    a += v;
+                }
+                if (x - i === 2 - (y - j)) {
+                    b += v;
+                }
+            }
+        }
+        if (a !== b) {
+            return 0;
+        }
+        for (let k = 0; k < 3; ++k) {
+            if (row[k] !== a || col[k] !== a) {
+                return 0;
+            }
+        }
+        return 1;
+    };
+    let ans = 0;
+    for (let i = 0; i < m; ++i) {
+        for (let j = 0; j < n; ++j) {
+            ans += check(i, j);
+        }
+    }
+    return ans;
+}
+```
+
+<!-- tabs:end -->
+
+<!-- solution:end -->
+
+<!-- solution:start -->
+
+### Solution 2
+
+<!-- tabs:start -->
+
+#### TypeScript
+
+```ts
+export function numMagicSquaresInside(grid: number[][]): number {
+    const [m, n] = [grid.length, grid[0].length];
+    if (m < 3 || n < 3) return 0;
+
+    const check = (y: number, x: number) => {
+        const g = grid;
+        if (g[y + 1][x + 1] !== 5) return 0;
+
+        const cells = [
+            g[y][x],
+            g[y][x + 1],
+            g[y][x + 2],
+            g[y + 1][x + 2],
+            g[y + 2][x + 2],
+            g[y + 2][x + 1],
+            g[y + 2][x],
+            g[y + 1][x],
+        ];
+
+        const i = cells.indexOf(2);
+        if (i === -1) return 0;
+        cells.push(...cells.splice(0, i));
+
+        const circle = [2, 9, 4, 3, 8, 1, 6, 7];
+        const reverseCircle = [2, 7, 6, 1, 8, 3, 4, 9];
+
+        if (cells.every((x, i) => x === circle[i])) return 1;
+        if (cells.every((x, i) => x === reverseCircle[i])) return 1;
+
+        return 0;
+    };
+
+    let res = 0;
+    for (let i = 0; i < m - 2; i++) {
+        for (let j = 0; j < n - 2; j++) {
+            res += check(i, j);
+        }
+    }
+
+    return res;
+}
+```
+
+#### JavaScript
+
+```js
+function numMagicSquaresInside(grid) {
+    const [m, n] = [grid.length, grid[0].length];
+    if (m < 3 || n < 3) return 0;
+
+    const check = (y, x) => {
+        const g = grid;
+        if (g[y + 1][x + 1] !== 5) return false;
+
+        const cells = [
+            g[y][x],
+            g[y][x + 1],
+            g[y][x + 2],
+            g[y + 1][x + 2],
+            g[y + 2][x + 2],
+            g[y + 2][x + 1],
+            g[y + 2][x],
+            g[y + 1][x],
+        ];
+
+        const i = cells.indexOf(2);
+        if (i === -1) return false;
+        cells.push(...cells.splice(0, i));
+
+        const circle = [2, 9, 4, 3, 8, 1, 6, 7];
+        const reverseCircle = [2, 7, 6, 1, 8, 3, 4, 9];
+
+        if (cells.every((x, i) => x === circle[i])) return true;
+        if (cells.every((x, i) => x === reverseCircle[i])) return true;
+
+        return false;
+    };
+
+    let res = 0;
+    for (let i = 0; i < m - 2; i++) {
+        for (let j = 0; j < n - 2; j++) {
+            res += +check(i, j);
+        }
+    }
+
+    return res;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/solution/0800-0899/0840.Magic Squares In Grid/README_EN.md b/solution/0800-0899/0840.Magic Squares In Grid/README_EN.md
index 5585d83cb0877..70ee41f412e26 100644
--- a/solution/0800-0899/0840.Magic Squares In Grid/README_EN.md	
+++ b/solution/0800-0899/0840.Magic Squares In Grid/README_EN.md	
@@ -314,6 +314,158 @@ function numMagicSquaresInside(grid: number[][]): number {
 }
 ```
 
+#### JavaScript
+
+```js
+function numMagicSquaresInside(grid) {
+    const m = grid.length;
+    const n = grid[0].length;
+    const check = (i, j) => {
+        if (i + 3 > m || j + 3 > n) {
+            return 0;
+        }
+        const cnt = Array(16).fill(0);
+        const row = Array(3).fill(0);
+        const col = Array(3).fill(0);
+        let [a, b] = [0, 0];
+        for (let x = i; x < i + 3; ++x) {
+            for (let y = j; y < j + 3; ++y) {
+                const v = grid[x][y];
+                if (v < 1 || v > 9 || ++cnt[v] > 1) {
+                    return 0;
+                }
+                row[x - i] += v;
+                col[y - j] += v;
+                if (x - i === y - j) {
+                    a += v;
+                }
+                if (x - i === 2 - (y - j)) {
+                    b += v;
+                }
+            }
+        }
+        if (a !== b) {
+            return 0;
+        }
+        for (let k = 0; k < 3; ++k) {
+            if (row[k] !== a || col[k] !== a) {
+                return 0;
+            }
+        }
+        return 1;
+    };
+    let ans = 0;
+    for (let i = 0; i < m; ++i) {
+        for (let j = 0; j < n; ++j) {
+            ans += check(i, j);
+        }
+    }
+    return ans;
+}
+```
+
+<!-- tabs:end -->
+
+<!-- solution:end -->
+
+<!-- solution:start -->
+
+### Solution 2
+
+<!-- tabs:start -->
+
+#### TypeScript
+
+```ts
+export function numMagicSquaresInside(grid: number[][]): number {
+    const [m, n] = [grid.length, grid[0].length];
+    if (m < 3 || n < 3) return 0;
+
+    const check = (y: number, x: number) => {
+        const g = grid;
+        if (g[y + 1][x + 1] !== 5) return 0;
+
+        const cells = [
+            g[y][x],
+            g[y][x + 1],
+            g[y][x + 2],
+            g[y + 1][x + 2],
+            g[y + 2][x + 2],
+            g[y + 2][x + 1],
+            g[y + 2][x],
+            g[y + 1][x],
+        ];
+
+        const i = cells.indexOf(2);
+        if (i === -1) return 0;
+        cells.push(...cells.splice(0, i));
+
+        const circle = [2, 9, 4, 3, 8, 1, 6, 7];
+        const reverseCircle = [2, 7, 6, 1, 8, 3, 4, 9];
+
+        if (cells.every((x, i) => x === circle[i])) return 1;
+        if (cells.every((x, i) => x === reverseCircle[i])) return 1;
+
+        return 0;
+    };
+
+    let res = 0;
+    for (let i = 0; i < m - 2; i++) {
+        for (let j = 0; j < n - 2; j++) {
+            res += check(i, j);
+        }
+    }
+
+    return res;
+}
+```
+
+#### JavaScript
+
+```js
+function numMagicSquaresInside(grid) {
+    const [m, n] = [grid.length, grid[0].length];
+    if (m < 3 || n < 3) return 0;
+
+    const check = (y, x) => {
+        const g = grid;
+        if (g[y + 1][x + 1] !== 5) return false;
+
+        const cells = [
+            g[y][x],
+            g[y][x + 1],
+            g[y][x + 2],
+            g[y + 1][x + 2],
+            g[y + 2][x + 2],
+            g[y + 2][x + 1],
+            g[y + 2][x],
+            g[y + 1][x],
+        ];
+
+        const i = cells.indexOf(2);
+        if (i === -1) return false;
+        cells.push(...cells.splice(0, i));
+
+        const circle = [2, 9, 4, 3, 8, 1, 6, 7];
+        const reverseCircle = [2, 7, 6, 1, 8, 3, 4, 9];
+
+        if (cells.every((x, i) => x === circle[i])) return true;
+        if (cells.every((x, i) => x === reverseCircle[i])) return true;
+
+        return false;
+    };
+
+    let res = 0;
+    for (let i = 0; i < m - 2; i++) {
+        for (let j = 0; j < n - 2; j++) {
+            res += +check(i, j);
+        }
+    }
+
+    return res;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/solution/0800-0899/0840.Magic Squares In Grid/Solution.js b/solution/0800-0899/0840.Magic Squares In Grid/Solution.js
new file mode 100644
index 0000000000000..fc08cda6431c1
--- /dev/null
+++ b/solution/0800-0899/0840.Magic Squares In Grid/Solution.js	
@@ -0,0 +1,45 @@
+function numMagicSquaresInside(grid) {
+    const m = grid.length;
+    const n = grid[0].length;
+    const check = (i, j) => {
+        if (i + 3 > m || j + 3 > n) {
+            return 0;
+        }
+        const cnt = Array(16).fill(0);
+        const row = Array(3).fill(0);
+        const col = Array(3).fill(0);
+        let [a, b] = [0, 0];
+        for (let x = i; x < i + 3; ++x) {
+            for (let y = j; y < j + 3; ++y) {
+                const v = grid[x][y];
+                if (v < 1 || v > 9 || ++cnt[v] > 1) {
+                    return 0;
+                }
+                row[x - i] += v;
+                col[y - j] += v;
+                if (x - i === y - j) {
+                    a += v;
+                }
+                if (x - i === 2 - (y - j)) {
+                    b += v;
+                }
+            }
+        }
+        if (a !== b) {
+            return 0;
+        }
+        for (let k = 0; k < 3; ++k) {
+            if (row[k] !== a || col[k] !== a) {
+                return 0;
+            }
+        }
+        return 1;
+    };
+    let ans = 0;
+    for (let i = 0; i < m; ++i) {
+        for (let j = 0; j < n; ++j) {
+            ans += check(i, j);
+        }
+    }
+    return ans;
+}
diff --git a/solution/0800-0899/0840.Magic Squares In Grid/Solution2.js b/solution/0800-0899/0840.Magic Squares In Grid/Solution2.js
new file mode 100644
index 0000000000000..b93fe320dce7b
--- /dev/null
+++ b/solution/0800-0899/0840.Magic Squares In Grid/Solution2.js	
@@ -0,0 +1,41 @@
+function numMagicSquaresInside(grid) {
+    const [m, n] = [grid.length, grid[0].length];
+    if (m < 3 || n < 3) return 0;
+
+    const check = (y, x) => {
+        const g = grid;
+        if (g[y + 1][x + 1] !== 5) return false;
+
+        const cells = [
+            g[y][x],
+            g[y][x + 1],
+            g[y][x + 2],
+            g[y + 1][x + 2],
+            g[y + 2][x + 2],
+            g[y + 2][x + 1],
+            g[y + 2][x],
+            g[y + 1][x],
+        ];
+
+        const i = cells.indexOf(2);
+        if (i === -1) return false;
+        cells.push(...cells.splice(0, i));
+
+        const circle = [2, 9, 4, 3, 8, 1, 6, 7];
+        const reverseCircle = [2, 7, 6, 1, 8, 3, 4, 9];
+
+        if (cells.every((x, i) => x === circle[i])) return true;
+        if (cells.every((x, i) => x === reverseCircle[i])) return true;
+
+        return false;
+    };
+
+    let res = 0;
+    for (let i = 0; i < m - 2; i++) {
+        for (let j = 0; j < n - 2; j++) {
+            res += +check(i, j);
+        }
+    }
+
+    return res;
+}
diff --git a/solution/0800-0899/0840.Magic Squares In Grid/Solution2.ts b/solution/0800-0899/0840.Magic Squares In Grid/Solution2.ts
new file mode 100644
index 0000000000000..2798cc4025b20
--- /dev/null
+++ b/solution/0800-0899/0840.Magic Squares In Grid/Solution2.ts	
@@ -0,0 +1,41 @@
+function numMagicSquaresInside(grid: number[][]): number {
+    const [m, n] = [grid.length, grid[0].length];
+    if (m < 3 || n < 3) return 0;
+
+    const check = (y: number, x: number) => {
+        const g = grid;
+        if (g[y + 1][x + 1] !== 5) return 0;
+
+        const cells = [
+            g[y][x],
+            g[y][x + 1],
+            g[y][x + 2],
+            g[y + 1][x + 2],
+            g[y + 2][x + 2],
+            g[y + 2][x + 1],
+            g[y + 2][x],
+            g[y + 1][x],
+        ];
+
+        const i = cells.indexOf(2);
+        if (i === -1) return 0;
+        cells.push(...cells.splice(0, i));
+
+        const circle = [2, 9, 4, 3, 8, 1, 6, 7];
+        const reverseCircle = [2, 7, 6, 1, 8, 3, 4, 9];
+
+        if (cells.every((x, i) => x === circle[i])) return 1;
+        if (cells.every((x, i) => x === reverseCircle[i])) return 1;
+
+        return 0;
+    };
+
+    let res = 0;
+    for (let i = 0; i < m - 2; i++) {
+        for (let j = 0; j < n - 2; j++) {
+            res += check(i, j);
+        }
+    }
+
+    return res;
+}