Js一些常用demo

/* jQuery代码 */
$(function () {
  $("#now-time").attr("onselectstart", "return false");//禁止选中文字
  $("#now-time").text(currentTime());
  setInterval(function () {
    $("#now-time").text(currentTime());
  }, 1000);
  /**
   * 获取最新时间/可使用BiugleJS挂在Date原型上的方法format获取当前时间new Date().format("yyyy-mm-dd h:i:s");
   * @returns {String}
   */
  function currentTime() {
    var date = new Date();
    var time;
    var year = date.getFullYear();
    var month = date.getMonth()+1;
    var day = date.getDate();
    var hour = date.getHours();
    var minute = date.getMinutes();
    var second = date.getSeconds();
    hour = (hour < 10) ? ("0" + hour) : hour;
    minute = (minute < 10) ? ("0" + minute) : minute;
    second = (second < 10) ? ("0" + second) : second;
    time = year + "年" + month + "月" + day + "日" + " " + hour + ":" + minute + ":" + second;
    return time;
  }
});

/**
 * 处理问题字符串
 * @param {String} 要处理的字符串。//可使用es6trim方法
 */
function formatStr(str) {
  str = str.replace(/^\s+|\s+$/g, "");//去掉前后空格
  //str = str.replace(/\s+/g,"");//去掉空格
  //str=str.replace( /^\s/, '');//去掉左空格
  //str=str.replace(/(\s$)/g, "");//去掉右空格
  let div = document.createElement('div');
  div.textContent = str;//利用textContent属性转化"<",">","&","'"等字符 
  let formatString = div.innerHTML;
  return formatString;
}

/**
 * 键盘事件
 * @param {Event} 当前按下的按键。SPA网站记得离开页面时off掉原有事件
 */
function addKeyboard(e) {
  //console.log(e.key);//获取键值
  var keyNum = window.event ? e.keyCode : e.which;
  //console.log(keyNum);
  if (keyNum === XXX) {
    //do something
  }
  if (keyNum === XXX && e.altKey) {
    //do something
  }
  if (keyNum === XXX && e.ctrlKey) {
    //do something
  }
}

/* 第一种方法 */
let a = document.querySelectorAll("a");
for(let i = 0; i < a.length; i++){
  console.log(a[i]);
}
--------------------------------------------------
/* 第二种方法 */
let A = document.querySelectorAll("a");
Array.prototype.filter.call(A, function (a) {
  console.log(a);
});

/* 取第一个值 */
for (let key in response) {
  result = response[key];
  break;
}
for (let value of response) {
   result = value;
   break;
}
/* 循环处理数组/对象 jquery举例子，更多js遍历数组方法不介绍了。 /

/ 需注意，除for...of，for，for...in之外，其他方法均不能强行跳出。 */

$.each([array/object], function (key, val) {

//do something

});
/* 例a /

$.each([1, 2], function(key, value) {

alert(index + ': ' + value);

});

/ 这将产生两个信息 /

/ 0: 52 /

/ 1: 97 */
/* 例b /

let obj = {

"a": "AAA",

"b": "BBB"

};

$.each(obj, function(key, value) {

alert( key + ": " + value );

});

/ 这将产生两个信息 /

/ a: AAA /

/ b: BBB /

/*


产生随机数
@param {Number} 随机数范围
@returns {Number} 产生的随机数

*/

function getRandnum(range) {

var num = Math.random() * range;

num = parseInt(num);

return num;

}

function consoleInfo() {

console.log("%c博客名称%cDoubleAm", "line-height:28px;padding:4px;background:#a1afc9;color:#000;font-size:16px;margin-right:15px", "color:#3fa9f5;line-height:28px;font-size:16px;");

console.log("%c网站地址%chttps://a.biugle.cn", "line-height:28px;padding:4px;background:#a1afc9;color:#000;font-size:16px;margin-right:15px", "color:#00bc12;line-height:28px;font-size:16px;");

console.log("%c扣扣号码%c1005760694", "line-height:28px;padding:4px;background:#a1afc9;color:#000;font-size:16px;margin-right:15px", "color:#ff9900;line-height:28px;font-size:16px;");

console.log("%c桃李春风一杯酒，江湖夜雨十年灯！", "line-height:28px;padding:5px;color:#fff;font-weight:bolder;font-size:16px;background-color:chocolate;color:#fff;");

if (window.console && window.console.log) {

console.log(%c页面加载消耗了 %c${(Math.round(100 * performance.now()) / 100 / 1e3).toFixed(2)}s, "background: #fff;color: #333;text-shadow: 0 0 2px #eee, 0 0 3px #eee, 0 0 3px #eee, 0 0 2px #eee, 0 0 3px #eee;", "color:tomato;font-weight:bolder;");

localStorage.getItem("access") || localStorage.setItem("access", (new Date).getTime());

let e = new Date(parseInt(localStorage.getItem("access")));

let o = ${e.getFullYear()}年${e.getMonth() + 1}月${e.getDate()}日;

let t = 0;

localStorage.getItem("hit") ? t = parseInt(localStorage.getItem("hit")) : localStorage.setItem("hit", 0);

localStorage.setItem("hit", ++t);

console.log(%c这是你自 %c${o} %c以来第 %c${t} %c次在本站打开控制台，你想知道什么秘密吗～, "", "color:chocolate;font-weight:bolder;", "", "color:chocolate;font-weight:bolder;", "");

}

}