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如何检查web上的选定文本是否仅由JavaScript中的单词组成?

selection html javascript

Seungho Lee · 技术社区 · 7 年前

在vanilla Javascript中,我试图确定用户在网页上选择的文本是否全部由单词组成(不包括符号)。

举个例子,,

假设我们在网页的某个地方有如下文本。

您好,以文本为例! (选择“全部”时)

应该导致 ['Hello', 'a', 'text', 'for', 'the', 'example']

然而,

赫尔 lo,以文本为例!

应该导致 ['a', 'text', 'for', 'the', 'example'] 自从 Hello 未完全选定为单词。

getSelectionText 函数,用于显示所有选定文本。

function getSelectionText() {
    var text = "";
    if (window.getSelection) {
        text = window.getSelection().toString();
    } else if (document.selection && document.selection.type !== "Control") {
        text = document.selection.createRange().text;
    }
    return text;
}

// Just adding the function as listeners.
document.onmouseup = document.onkeyup = function() {
    console.log(getSelectionText());
};

1 回复 | 直到 7 年前

nem035 7 年前

一种方法是有一本包含所有英语单词的完整词典。

const setOfAllEnglishWords = new Set([
  "Hello",
  "a",
  "text",
  "for",
  "the",
  "example"
  // ... many many more
]);

const selection = "lo, a text for the example!";
const result = selection
  .replace(/[^A-Za-z0-9\s]/g, "") // remove punctuation by replacing anything that is not a letter or a digit with the empty string
  .split(/\s+/)                   // split text into words by using 1 or more whitespace as the break point
  .filter(word => setOfAllEnglishWords.has(word));

console.log(result);

218632 话。平均字长为 4.5 信件和JS商店 2 218632 * (4.5 * 2) = 1967688 B = 1.967 MB ,在慢速3G连接上下载可能需要1分钟。

function getSetOfWordsOnPage() {
  const walk = document.createTreeWalker(
    document.body,
    NodeFilter.SHOW_TEXT
  );

  const dict = new Set();
  let n;
  while ((n = walk.nextNode())) {
    for (const word of n.textContent
      .replace(/[^A-Za-z0-9\s]/g, "")
      .split(/\s+/)
      .map(word => word.trim())
      .filter(word => !!word)) {
      dict.add(word);
    }
  }
  return dict;
}

const setOfWordsOnThePage = getSetOfWordsOnPage();

function getSelectionText() {
  if (window.getSelection) {
    return window.getSelection().toString();
  } else if (document.selection && document.selection.type !== "Control") {
    return document.selection.createRange().text;
  }
  return "";
}

// Just adding the function as listeners.
document.querySelector("#button").addEventListener("click", () => {
  const result = getSelectionText()
    .replace(/[^A-Za-z0-9\s]/g, "") // remove punctuation
    .split(/\s+/) // split text into words
    .filter(word => setOfWordsOnThePage.has(word));
  console.log(result);
});

<button id="button">Show result</button>
<p>this is some text</p>
<p>again this is a text!!!!!</p>
<p>another,example,of,a,sentence</p>

也许我们可以更进一步。我们甚至需要记住单词吗?“单词是由空格包围的文本”的定义似乎已经足够了。

为了减少记住页面上单词的不必要开销,并解决部分选择有效单词的错误,我们可以在选择后立即检查所选区域最左侧(锚定)和最右侧(焦点)节点的内容,如果它们包含其他未选择的文本,则忽略它们。

我们在这里做的假设是,对于任意选择的文本,我们最多可以有2个部分选择的单词,每个选择端一个。

注: 下面的方法还通过假设 THIS tHiS ,及 this 都是同一个词。

function removePunctuation(string) {
  return string.replace(/[^A-Za-z0-9\s]/g, " ");
}

function splitIntoWords(string) {
  return removePunctuation(string)
    .split(/\s+/)
    .map(word => word.toLowerCase().trim())
    .filter(word => !!word);
}

function getSelectedWords() {
  const selection = window.getSelection();
  const words = splitIntoWords(selection.toString());

  if (selection.anchorNode) {
    const startingsWords = splitIntoWords(selection.anchorNode.textContent);
    if (words[0] !== startingsWords[0]) {
      words.shift(); // remove the start since it's not a whole word
    }
  }

  if (selection.focusNode) {
    const endingWords = splitIntoWords(selection.focusNode.textContent);
    if (words[words.length - 1] !== endingWords[endingWords.length - 1]) {
      words.pop(); // remove the end since it's not a whole word
    }
  }

  return words;
}

// Just adding the function as listeners.
document.querySelector("#button").addEventListener("click", () => {
  console.log(getSelectedWords());
});

<button id="button">Show result</button>
<p><div>this is</div> <div>some text</div></p>
<p><span>again</span><span> </span><span>this</span><span> </span><span>is</span><span> </span><span>a</span> <span>text</span><span>!!!!!</span></p>
<p>another,example,of,a,sentence</p>

注: 如果您将单词分解为多个html元素,则此代码仍然会中断 word