JavaScript代码段

addEventListener.js

function addEventHandler (target, type, func) {
  if (target.addEventListener) {
    target.addEventListener(type, func, false);
  } else if (target.attachEvent) {
    target.attachEvent('on' + type, func);
  } else {
    target['on' + type] = func;
  }
}

addUrlParam.js

var addUrlParam = function(search, key, val){
  var newParam = key + '=' + val,
      params = '?' + newParam;

  // If the "search" string exists, then build params from it
  if (search) {
    // Try to replace an existance instance
    params = search.replace(new RegExp('([?&])' + key + '[^&]*'), '$1' + newParam);

    // If nothing was replaced, then add the new param to the end
    if (params === search) {
      params += '&' + newParam;
    }
  }

  return params;
};

array_remove_duplicate.js

//普通数组去重
return Array.from(new Set(arr))

//含对象数组去重
function unique (arr) {
  let result = {}
  let finalResult = []
  for(let i = 0; i < arr.length; i++) {
    result[arr[i].teacher + arr[i].name] = arr[i]
    //因为arr[i].name不能重复,达到去重效果,且这里必须知晓"name"或是其他键名
  }
  //现在result内部都是不重复的对象了，只需要将其键值取出来转为数组即可
  for (let item in result) {
    finalResult.push(result[item])
  }
  return finalResult
}

debounce.js

// underscore的debouce

function restArgs(func, startIndex) {
  startIndex = startIndex == null ? func.length - 1 : +startIndex
  return function() {
    var length = Math.max(arguments.length - startIndex, 0),
        rest = Array(length),
        index = 0
    for ( ;index < length; index++) {
      rest[index] = arguments[index + startIndex]
    }
    switch (startIndex) {
      case 0: return func.call(this, rest)
      case 1: return func.call(this, arguments[0], rest)
      case 2: return func.call(this, arguments[0], arguments[1], rest)
    }
    var args = Array(startIndex + 1)
    for (index = 0; index < startIndex; index++) {
      args[index] = arguments[index]
    }
    args[startIndex] = rest
    return func.apply(this, args)
  }
}

var delay = restArgs(function(func, wait, args) {
  return setTimeout(function() {
    return func.apply(null, args)
  }, wait)
})

function debounce(func, wait, immediate) {
  var timeout, result

  var later = function(context, args) {
    timeout = null
    if (args) result = func.apply(context, args)
  }

  var debounced = restArgs(function(args) {
    if (timeout) clearTimeout(timeout)
    if (immediate) {
      var callNow = !timeout
      timeout = setTimeout(later, wait)
      if (callNow) result = func.apply(this, args)
    } else {
      timeout = delay(later, wait, this, args)
    }

    return result
  })

  debounced.cancel = function() {
    clearTimeout(timeout)
    timeout = null
  }

  return debounced
}

get_local_json.js

//Retrive array data in local json file
$.getJSON(`filename.json`).done(function (data) {
  if (data) {
    data.forEach(function (item, index) {
      //dosomething
    })
  }
})

getSelectionSentence.js

// 获取选取周围句子

const INLINE_TAGS = new Set([
  // Inline text semantics
  'a', 'abbr', 'b', 'bdi', 'bdo', 'br', 'cite', 'code', 'data', 'dfn', 'em', 'i',
  'kbd', 'mark', 'q', 'rp', 'rt', 'rtc', 'ruby', 's', 'samp', 'small',
  'span', 'strong', 'sub', 'sup', 'time', 'u', 'var', 'wbr'
])

/**
* @returns {string}
*/
function getSelectionSentence (slt) {
  const sentenceHeadTester = /((\.(?![ .]))|[^.?!。？！…\r])+$/
  const sentenceTailTester = /^((\.(?![ .]))|[^.?!。？！…\r])+(.)\3{0,2}/
  const selection = slt
  const selectedText = slt.toString()
  if (!selectedText.trim()) { return '' }

  var sentenceHead = ''
  var sentenceTail = ''

  const anchorNode = selection.anchorNode
  if (anchorNode.nodeType === Node.TEXT_NODE) {
    let leadingText = anchorNode.textContent.slice(0, selection.anchorOffset)
    for (let node = anchorNode.previousSibling; node; node = node.previousSibling) {
      if (node.nodeType === Node.TEXT_NODE) {
        leadingText = node.textContent + leadingText
      } else if (node.nodeType === Node.ELEMENT_NODE) {
        leadingText = node.innerText + leadingText
      }
    }

    for (
      let element = anchorNode.parentElement;
      element && INLINE_TAGS.has(element.tagName.toLowerCase()) && element !== document.body;
      element = element.parentElement
    ) {
      for (let el = element.previousElementSibling; el; el = el.previousElementSibling) {
        leadingText = el.innerText + leadingText
      }
    }

    sentenceHead = (leadingText.match(sentenceHeadTester) || [''])[0]
  }

  const focusNode = selection.focusNode
  if (selection.focusNode.nodeType === Node.TEXT_NODE) {
    let tailingText = selection.focusNode.textContent.slice(selection.focusOffset)
    for (let node = focusNode.nextSibling; node; node = node.nextSibling) {
      if (node.nodeType === Node.TEXT_NODE) {
        tailingText += node.textContent
      } else if (node.nodeType === Node.ELEMENT_NODE) {
        tailingText += node.innerText
      }
    }

    for (
      let element = focusNode.parentElement;
      element && INLINE_TAGS.has(element.tagName.toLowerCase()) && element !== document.body;
      element = element.parentElement
    ) {
      for (let el = element.nextElementSibling; el; el = el.nextElementSibling) {
        tailingText += el.innerText
      }
    }

    sentenceTail = (tailingText.match(sentenceTailTester) || [''])[0]
  }

  return (sentenceHead + selectedText + sentenceTail)
    .replace(/(^\s+)|(\s+$)/gm, '\n') // allow one empty line & trim each line
    .replace(/(^\s+)|(\s+$)/g, '') // remove heading or tailing \n
}

let slt = window.getSelection()
getSelectionSentence(slt)

how_to_delete_array_item.js

/**
 * JavaScript Tools
 * @Qia YANG (https://imqia.me/)
 * @date    2016-12-24 21:54:40
 * two ways to delete an item in an array
 */

var myArray = ["a", "b", "c"];
delete myArray[0]; // => [null, "b", "c"]
myArray.splice(0, 1); // => ["b", "c"]

/**
 * About Array.prototype.splice()
 * Syntax:
 * array.splice(start, deleteCount, item1, item2, ...)
 * For example:
**/
myArray.splice(1, 0, "d"); // => ["a", "b", "d", "c"]

importorexport_json_file_in_chrome_extension.js

// 在Chrome插件中import/export本地文件

// export
var MyArray = [elem1, elem2, ....];
var _myArray = JSON.stringify(MyArray , null, 4); //indentation in json format, human readable

var vLink = document.createElement('a'),
vBlob = new Blob([_myArray], {type: "octet/stream"}),
vName = 'watever_you_like_to_call_it.json',
vUrl = window.URL.createObjectURL(vBlob);
vLink.setAttribute('href', vUrl);
vLink.setAttribute('download', vName );
vLink.click();

// import
// <input type="file" id="importOrig" accept=".json" style="display:none"/>
importOrig.addEventListener("change", importFun, false);

fakeImp.onclick = function () {importOrig.click()}

function importFun(e) {
  var files = e.target.files, reader = new FileReader();
  reader.onload = _imp;
  reader.readAsText(files[0]);
}

function _imp() {
  var _myImportedData = JSON.parse(this.result);
  //here is your imported data, and from here you should know what to do with it (save it to some storage, etc.)

  ......
  importOrig.value = ''; //make sure to clear input value after every import
}

regexp.js

// 分割html标签
arr = html.split(/<\/?[\w\s="/.':;#-\/\?]+>/ig)

// Remove newline
/(\r\n\t|\n|\r\t)/g
  
// Multiple spaces
/ +(?= )/g

// Html entities
/&[#A-Za-z0-9]+;/gi
    
// Script tag and its content
/<script[^>]*>(?:(?!<\/script>)[^])*<\/script>/gi

to_back_top.js

/*
获取滚动条垂直偏移量的函数
除了IE8及更早版本，其他浏览器可以使用Window对象的PageYOffset属性
同时可以通过scrollTop属性来获取。
*/
function getScrollTop(){
    //IE8及更早版本没有window.pageYOffset属性
    if(window.pageYOffset != null){
        return window.pageYOffset;
    }

    //标准模式查询document.documentElement
    if(document.compatMode == "CSS1Compat"){
        return window.document.documentElement.scrollTop;
    }

    //怪异模式查询document.body
    return window.document.body.scrollTop;
}

function backTop(){
    var top = getScrollTop();  

    if (top > 0) {  
        //用计时器设置每隔10毫秒调用自身滚动一部分
        //模拟拉动滚动条效果
        //arguments.callee指向当前调用的函数本身
        window.scrollTo(0, top / 1.05);
        setTimeout(arguments.callee, 10);  
    }
}

//将函数绑定到相应事件
btn.onclick = backTop;