一个UTF-16字符串，JavaScript 正是使用了这种编码的字符串，所以 DOMString 直接被映射为（is mapped directly to）String。
规范
| Specification | Status | Comment |
|---|---|---|
| Web IDL (Second Edition) DOMString |
Candidate Recommendation | Rephrasing of the definition to remove weird edge cases. |
| Document Object Model (DOM) Level 3 Core Specification DOMString |
Recommendation | No change from Document Object Model (DOM) Level 2 Core Specification |
| Document Object Model (DOM) Level 2 Core Specification DOMString |
Recommendation | No change from Document Object Model (DOM) Level 1 Specification |
| Document Object Model (DOM) Level 1 Specification DOMString |
Recommendation | Initial definition. |