添加 704. 二分查找 javaScript版本

problems/0704.二分查找.md

@@ -254,6 +254,43 @@ func search(nums []int, target int) int {
 }
 ```
 
+javaScript
+
+```js
+
+// （版本一）左闭右闭区间
+
+var search = function(nums, target) {
+    let l = 0, r = nums.length - 1;
+    // 区间 [l, r]
+    while(l <= r) {
+        let mid = (l + r) >> 1;
+        if(nums[mid] === target) return mid;
+        let isSmall = nums[mid] < target;
+        l = isSmall ? mid + 1 : l;
+        r = isSmall ? r : mid - 1;
+    }
+    return -1;
+};
+
+// （版本二）左闭右开区间
+
+var search = function(nums, target) {
+    let l = 0, r = nums.length;
+    // 区间 [l, r）
+    while(l < r) {
+        let mid = (l + r) >> 1;
+        if(nums[mid] === target) return mid;
+        let isSmall = nums[mid] < target;
+        l = isSmall ? mid + 1 : l;
+        // 所以 mid 不会被取到
+        r = isSmall ? r : mid;
+    }
+    return -1;
+};
+
+```
+