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// Copyright 2013 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @fileoverview HTML processing utilities for HTML in string form.
*/
goog.provide('goog.html.utils');
goog.require('goog.string');
/**
* Extracts plain text from HTML.
*
* This behaves similarly to extracting textContent from a hypothetical DOM
* element containing the specified HTML. Block-level elements such as div are
* surrounded with whitespace, but inline elements are not. Span is treated as
* a block level element because it is often used as a container. Breaking
* spaces are compressed and trimmed.
*
* @param {string} value The input HTML to have tags removed.
* @return {string} The plain text of value without tags, HTML comments, or
* other non-text content. Does NOT return safe HTML!
*/
goog.html.utils.stripHtmlTags = function(value) {
// TODO(user): Make a version that extracts text attributes such as alt.
return goog.string.unescapeEntities(
goog.string.trim(
value
.replace(
goog.html.utils.HTML_TAG_REGEX_,
function(fullMatch, tagName) {
return goog.html.utils.INLINE_HTML_TAG_REGEX_.test(
tagName) ?
'' :
' ';
})
.replace(/[\t\n ]+/g, ' ')));
};
/**
* Matches all tags that do not require extra space.
*
* @private @const
*/
goog.html.utils.INLINE_HTML_TAG_REGEX_ =
/^(?:abbr|acronym|address|b|em|i|small|strong|su[bp]|u)$/i;
/**
* Matches all tags, HTML comments, and DOCTYPEs in tag soup HTML.
* By removing these, and replacing any '<' or '>' characters with
* entities we guarantee that the result can be embedded into
* an attribute without introducing a tag boundary.
*
* @private @const
*/
goog.html.utils.HTML_TAG_REGEX_ = /<[!\/]?([a-z0-9]+)([\/ ][^>]*)?>/gi;
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