# groonga - An open-source fulltext search engine and column store.

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# 7.12.8. html_untag

## 7.12.8.1. Summary

`html_untag` strips HTML tags from HTML and outputs plain text.

`html_untag` is used in `--output_columns` described at output_columns.

## 7.12.8.2. Syntax

`html_untag` requires only one argument. It is `html`.

    html_untag(html)

## 7.12.8.3. Requirements

`html_untag` requires Groonga 3.0.5 or later.

`html_untag` requires コマンドバージョン 2 or later.

## 7.12.8.4. Usage

Here are a schema definition and sample data to show usage.

Sample schema:

Execution example:

    table_create WebClips TABLE_HASH_KEY ShortText
    # [[0, 1337566253.89858, 0.000355720520019531], true]
    column_create WebClips content COLUMN_SCALAR ShortText
    # [[0, 1337566253.89858, 0.000355720520019531], true]

Sample data:

Execution example:

    load --table WebClips
    [
    {"_key": "http://groonga.org", "content": "groonga is <span class='emphasize'>fast</span>"},
    {"_key": "http://mroonga.org", "content": "mroonga is <span class=\"emphasize\">fast</span>"},
    ]
    # [[0, 1337566253.89858, 0.000355720520019531], 2]

Here is the simple usage of `html_untag` function which strips HTML tags from content of column.

Execution example:

    select WebClips --output_columns "html_untag(content)" --command_version 2
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     [
    #       [
    #         2
    #       ],
    #       [
    #         [
    #           "html_untag",
    #           "null"
    #         ]
    #       ],
    #       [
    #         "groonga is fast"
    #       ],
    #       [
    #         "mroonga is fast"
    #       ]
    #     ]
    #   ]
    # ]

When executing the above query, you can see "span" tag with "class" attribute is stripped. Note that you must specify `--command_version 2` to use `html_untag` function.

## 7.12.8.5. Parameters

There is one required parameter, `html`.

### 7.12.8.5.1. `html`

It specifies HTML text to be untagged.

## 7.12.8.6. Return value

`html_untag` returns plain text which is stripped HTML tags from HTML text.