JavaScript 有用的代码片段和 trick(2)

注:更多方法请参考《How to flatten nested array in JavaScript?》

日期格式化

// 方法一
function format1(x, y) {
 var z = {
 y: x.getFullYear(),
 M: x.getMonth() + 1,
 d: x.getDate(),
 h: x.getHours(),
 m: x.getMinutes(),
 s: x.getSeconds()
 };
 return y.replace(/(y+|M+|d+|h+|m+|s+)/g, function(v) {
 return ((v.length > 1 ? "0" : "") + eval('z.' + v.slice(-1))).slice(-(v.length > 2 ? v.length : 2))
 });
}

format1(new Date(), 'yy-M-d h:m:s'); // 17-10-14 22:14:41

// 方法二
Date.prototype.format = function (fmt) { 
 var o = {
 "M+": this.getMonth() + 1, //月份 
 "d+": this.getDate(), //日 
 "h+": this.getHours(), //小时 
 "m+": this.getMinutes(), //分 
 "s+": this.getSeconds(), //秒 
 "q+": Math.floor((this.getMonth() + 3) / 3), //季度 
 "S": this.getMilliseconds() //毫秒 
 };
 if (/(y+)/.test(fmt)){
 fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
 } 
 for (var k in o){
 if (new RegExp("(" + k + ")").test(fmt)){
  fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
 }
 }  
 return fmt;
}
new Date().format('yy-M-d h:m:s'); // 17-10-14 22:18:17

特殊字符转义

function htmlspecialchars (str) {
 var str = str.toString().replace(/&/g, "&").replace(/</g, "<").replace(/>/g, ">").replace(/"/g, '"');
 return str;
}
htmlspecialchars('&jfkds<>'); // "&jfkds<>"

动态插入js

function injectScript(src) {
 var s, t;
 s = document.createElement('script');
 s.type = 'text/javascript';
 s.async = true;
 s.src = src;
 t = document.getElementsByTagName('script')[0];
 t.parentNode.insertBefore(s, t);
}

格式化数量

// 方法一
function formatNum (num, n) {
 if (typeof num == "number") {
 num = String(num.toFixed(n || 0));
 var re = /(-?\d+)(\d{3})/;
 while (re.test(num)) num = num.replace(re, "$1,$2");
 return num;
 }
 return num;
}
formatNum(2313123, 3); // "2,313,123.000"
// 方法二
'2313123'.replace(/\B(?=(\d{3})+(?!\d))/g, ','); // "2,313,123"
// 方法三
function formatNum(str) {
 return str.split('').reverse().reduce((prev, next, index) => {
 return ((index % 3) ? next : (next + ',')) + prev
 });
}
formatNum('2313323'); // "2,313,323"

身份证验证

function chechCHNCardId(sNo) {
 if (!this.regExpTest(sNo, /^[0-9]{17}[X0-9]$/)) {
 return false;
 }
 sNo = sNo.toString();

 var a, b, c;
 a = parseInt(sNo.substr(0, 1)) * 7 + parseInt(sNo.substr(1, 1)) * 9 + parseInt(sNo.substr(2, 1)) * 10;
 a = a + parseInt(sNo.substr(3, 1)) * 5 + parseInt(sNo.substr(4, 1)) * 8 + parseInt(sNo.substr(5, 1)) * 4;
 a = a + parseInt(sNo.substr(6, 1)) * 2 + parseInt(sNo.substr(7, 1)) * 1 + parseInt(sNo.substr(8, 1)) * 6;
 a = a + parseInt(sNo.substr(9, 1)) * 3 + parseInt(sNo.substr(10, 1)) * 7 + parseInt(sNo.substr(11, 1)) * 9;
 a = a + parseInt(sNo.substr(12, 1)) * 10 + parseInt(sNo.substr(13, 1)) * 5 + parseInt(sNo.substr(14, 1)) * 8;
 a = a + parseInt(sNo.substr(15, 1)) * 4 + parseInt(sNo.substr(16, 1)) * 2;
 b = a % 11;

 if (b == 2) {
 c = sNo.substr(17, 1).toUpperCase();
 } else {
 c = parseInt(sNo.substr(17, 1));
 }

 switch (b) {
 case 0:
  if (c != 1) {
  return false;
  }
  break;
 case 1:
  if (c != 0) {
  return false;
  }
  break;
 case 2:
  if (c != "X") {
  return false;
  }
  break;
 case 3:
  if (c != 9) {
  return false;
  }
  break;
 case 4:
  if (c != 8) {
  return false;
  }
  break;
 case 5:
  if (c != 7) {
  return false;
  }
  break;
 case 6:
  if (c != 6) {
  return false;
  }
  break;
 case 7:
  if (c != 5) {
  return false;
  }
  break;
 case 8:
  if (c != 4) {
  return false;
  }
  break;
 case 9:
  if (c != 3) {
  return false;
  }
  break;
 case 10:
  if (c != 2) {
  return false;
  };
 }
 return true;
}
      

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