> For the complete documentation index, see [llms.txt](https://jack80342.gitbook.io/thymeleaf/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jack80342.gitbook.io/thymeleaf/i.-using-thymeleaf/19-fu-lubbiao-da-shi-yong-dui-xiang/ids.md).

# ID

* **#ids**: 处理可能重复(比如，由于迭代）的`id`属性的实用方法。

```java
/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Ids
 * ======================================================================
 */

/*
 * Normally used in th:id attributes, for appending a counter to the id attribute value
 * so that it remains unique even when involved in an iteration process.
 */
${#ids.seq('someId')}

/*
 * Normally used in th:for attributes in <label> tags, so that these labels can refer to Ids
 * generated by means if the #ids.seq(...) function.
 *
 * Depending on whether the <label> goes before or after the element with the #ids.seq(...)
 * function, the "next" (label goes before "seq") or the "prev" function (label goes after 
 * "seq") function should be called.
 */
${#ids.next('someId')}
${#ids.prev('someId')}
```