diff --git a/problems/0205.同构字符串.md b/problems/0205.同构字符串.md
index 5d20aa4a..1b4d0e32 100644
--- a/problems/0205.同构字符串.md
+++ b/problems/0205.同构字符串.md
@@ -119,6 +119,25 @@ func isIsomorphic(s string, t string) bool {
 ## JavaScript
 
 ```js
+var isIsomorphic = function(s, t) {
+    let len = s.length;
+    if(len === 0) return true;
+    let maps = new Map();
+    let mapt = new Map();
+    for(let i = 0, j = 0; i < len; i++, j++){
+        if(!maps.has(s[i])){
+            maps.set(s[i],t[j]);// maps保存 s[i] 到 t[j]的映射
+        } 
+        if(!mapt.has(t[i])){
+            mapt.set(t[j],s[i]);// mapt保存 t[j] 到 s[i]的映射
+        }
+        // 无法映射，返回 false
+        if(maps.get(s[i]) !== t[j] || mapt.get(t[j]) !== s[i]){
+            return false;
+        }
+    };
+    return true;
+};
 ```
 
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