feat: add js solution to lc problem: No.1704 (doocs#980)

Author: Qiu-IT

solution/1700-1799/1704.Determine if String Halves Are Alike/README.md

@@ -193,6 +193,24 @@ class Solution {
 }
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var halvesAreAlike = function (s) {
+    const str = 'aeiouAEIOU';
+    let cnt = 0;
+    for (let i = 0; i < s.length / 2; i++) {
+        if (str.indexOf(s[i]) > -1) cnt++;
+        if (str.indexOf(s[s.length - 1 - i]) > -1) cnt--;
+    }
+    return cnt === 0;
+};
+```
+
 ### **...**
 
 ```

solution/1700-1799/1704.Determine if String Halves Are Alike/README_EN.md

@@ -177,6 +177,24 @@ class Solution {
 }
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var halvesAreAlike = function (s) {
+    const str = 'aeiouAEIOU';
+    let cnt = 0;
+    for (let i = 0; i < s.length / 2; i++) {
+        if (str.indexOf(s[i]) > -1) cnt++;
+        if (str.indexOf(s[s.length - 1 - i]) > -1) cnt--;
+    }
+    return cnt === 0;
+};
+```
+
 ### **...**
 
 ```

solution/1700-1799/1704.Determine if String Halves Are Alike/Solution.js

@@ -0,0 +1,13 @@
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var halvesAreAlike = function (s) {
+    const str = 'aeiouAEIOU';
+    let cnt = 0;
+    for (let i = 0; i < s.length / 2; i++) {
+        if (str.indexOf(s[i]) > -1) cnt++;
+        if (str.indexOf(s[s.length - 1 - i]) > -1) cnt--;
+    }
+    return cnt === 0;
+};