javascript
JavaScript
判断是否为整数，是返回true，不是返回false
//判断是否为整数
function isInteger(num) {
let str = num + '';
if (str.indexOf('.') == -1) {
return true;
} else {
return false;
}
}输入年份，得到当年的二月天数
//输入年份得到二月天数
function getFebruaryDay(day) {
if (day % 4 == 0 && day % 100 != 0 || day % 400 == 0) {
document.writeln(day + '是闰年，二月有29天' + '<br>');
} else {
document.writeln(day + '是平年，二月有28天' + '<br>');
}
}
// 输入年份得到二月天数
function acquireFebruaryDay(year) {
var date1 = new Date(year + '/02/01');
var date2 = new Date(year + '/03/01');
var time1 = date1.getTime();
var time2 = date2.getTime();
console.log((time2 - time1) / 1000 / 60 / 60 / 24 + '天');
}
acquireFebruaryDay(2008);输入三角形行数，打印该行数的三角形
//输入行数，打印三角形
function triangle(rowCount) {
rowCount = parseInt(rowCount);
for (let i = 1; i <= rowCount; i++) {
for (let x = rowCount - i - 1; x >= 0; x--) {
document.write(' ');
}
for (let y = 1; y <= 2 * i - 1; y++) {
document.write('<span style="font-weight:700">*</span>');
}
document.write('<br>');
}
}
triangle(10);输入最小值min和最大值max，输出该范围内的素数，范围：[min,max]
//打印指定范围内的素数
function primrNumber(mix, max) {
for (let i = mix; i <= max; i++) {
let flag = true;
for (let j = 2; j < i; j++) {
if (i % j == 0) {
flag = false;
break;
}
}
if (flag) {
document.writeln(i);
}
}
}
primrNumber(1, 100);计算表达式1-2+3-4+5-6+...+n的值,输入n的值
//计算表达式1-2+3-4+5-6+...+n的值
function cal(n) {
n = parseInt(n);
let sum = 0;
for (let i = 1; i <= n; i++) {
let num = i;
if (i % 2 == 0) {
num = (-1) * i;
}
sum += num;
}
document.write(sum);
}
cal(prompt('请输入n的值：'));求4位数的前2位数和后两位数相等，且能开方的4位数
//4位数 前2位和后两位相等 且4位数能开方
function fourFigures() {
for (let i = 1000; i <= 9999; i++) {
// let kilobit = i / 1000;
// let hundreds = i / 100 % 10;
// let decade = i / 10 % 10;
// let unit = i % 10;
let beforeNum = parseInt(i / 100);
let afterNum = i % 100;
if (isInteger(i) && beforeNum == afterNum) {
console.log(i);
}
}
};
fourFigures();随机数
// 返回了一个在指定值之间的随机数。这个值不小于 min（有可能等于），并且小于（不等于）max
function getRandom(min, max) {
return Math.floor(Math.random() * (max - min + 1)) + min;
}
// 返回了一个在指定值之间的随机数。包含min和max
function getRandomIntInclusive(min, max) {
min = Math.ceil(min);
max = Math.floor(max);
return Math.floor(Math.random() * (max - min + 1)) + min; //含最大值，含最小值
}
// 生成包含最大值和最小值的随机数
function getRandomNum(min, max) {
return parseInt(Math.random() * (max - min + 1)) + min;
}斐波那契数列
count为数列的第几位
//递归
function frog(count) {
if (count == 1) {
return 1;
} else if (count == 2) {
return 2;
} else {
return frog(count - 2) + frog(count - 1);
}
}
//循环
let result = 0,
n1 = 1,
n2 = 2;
for (let i = 3; i <= 20; i++) {
result = n1 + n2;
n1 = n2;
n2 = result;
console.log(i + '->' + result);
}
document.writeln(result);返回当前日期
function getDateTime() {
let date = new Date();
let year = date.getFullYear();
let month = date.getMonth() + 1; // [0-11]
let day = date.getDate();
let hour = date.getHours();
let minutes = date.getMinutes();
let senconds = date.getSeconds();
hour = (hour < 10 ? ('0' + hour) : hour);
minutes = (minutes < 10 ? ('0' + minutes) : minutes);
senconds = (senconds < 10 ? ('0' + senconds) : senconds);
// return year + '年' + month + '月' + day + '日' + hour + '时' + minutes + '分' + senconds + '秒';
return year + '年' + month + '月' + day + '日' + hour + ':' + minutes + ':' + senconds;
}计算指定日期到现在日期的天数
function setDateTime(birday) {
let bti = parseInt((new Date(birday).getTime()) / 1000 / 60 / 60 / 24);
let now = parseInt(Date.now() / 1000 / 60 / 60 / 24);
return now - bti + '天';
}
console.log(setDateTime('2000/1/11'));数组排序
0 升序
1 降序
/***
* 数组排序
* arr 传入数组
* flag 0升序 1降序
* 对原数组操作返回新数组
***/
function sort(arr, flag) {
for (let i = 0; i < arr.length; i++) {
for (let j = 0; j < arr.length - i - 1; j++) {
// 升序
if (flag == 0) {
if (arr[j] > arr[j + 1]) {
let temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
//降序
if (flag == 1) {
if (arr[j] < arr[j + 1]) {
let temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
return arr;
}数组去重
//去除数组重复数据
function Delete_Duplicate_Elements(arr) {
var newarr = [];
for (var i = 0; i < arr.length; i++) {
if (newarr.indexOf(arr[i]) == -1)
newarr.push(arr[i]);
}
return newarr;
}JavaSript API | 腾讯位置服务
https://lbs.qq.com/webApi/javascriptGL/glGuide/glOverview
获取URL参数
QueryString: function (item, href) {
var str = location.search;
if (arguments.length == 2) str = href;
var svalue = str.match(new RegExp("[\?\&]" + item + "=([^\&]*)(\&?)", "i"));
return svalue ? unescape(svalue[1]) : svalue;
}
//获取url中"?"符后的字串
GetAllQueryString: function () {
var url = location.search;
if (url.indexOf("?") != -1) {
var str = url.substr(1);
return str;
}
return null;
}判断对象是否是NULL或者时undefined
IsEmpty: function (val) {//判断对象是否是NULL或者时undefined
if (typeof (val) == 'undefined') return true;
if (val == null || val == "null" || val == "undefined") return true;
if ((val + "").replace(/ /g, "").trim() == "") return true;
return false;
}数值相加
numberValueAdd: function (arg1, arg2) {
var r1, r2, m;
try { r1 = arg1.toString().split(".")[1].length; } catch (e) { r1 = 0; }
try { r2 = arg2.toString().split(".")[1].length; } catch (e) { r2 = 0; }
m = Math.pow(10, Math.max(r1, r2));
var r = this.numberValueMultiply(arg1, m) + this.numberValueMultiply(arg2, m);
var result = this.numberValueDivide(r, m);
if (isNaN(result)) {
result = 0;
}
return result;
}数值相减
numberValueSubtract: function (arg1, arg2) {
var r1, r2, m;
try { r1 = arg1.toString().split(".")[1].length; } catch (e) { r1 = 0; }
try { r2 = arg2.toString().split(".")[1].length; } catch (e) { r2 = 0; }
m = Math.pow(10, Math.max(r1, r2));
var r = this.numberValueMultiply(arg1, m) - this.numberValueMultiply(arg2, m);
var result = this.numberValueDivide(r, m);
if (isNaN(result)) {
result = 0;
}
return result;
},数值相除
numberValueDivide: function (arg1, arg2) {
if (arg2 === 0) return 0;
var t1 = 0, t2 = 0, r1, r2;
if (IsEmpty(arg1)) arg1 = 0;
if (IsEmpty(arg2)) {
arg2 = 1;
arg1 = 0;
};
try { t1 = arg1.toString().split(".")[1].length; } catch (e) { }
try { t2 = arg2.toString().split(".")[1].length; } catch (e) { }
with (Math) {
r1 = Number(arg1.toString().replace(".", ""));
r2 = Number(arg2.toString().replace(".", ""));
return (r1 / r2) * pow(10, t2 - t1);
}
}数值相乘
numberValueMultiply: function (arg1, arg2) {
if (IsEmpty(arg1)) arg1 = 0;
if (IsEmpty(arg2)) arg2 = 0;
var m = 0, s1 = arg1.toString(), s2 = arg2.toString();
try { m += s1.split(".")[1].length; } catch (e) { }
try { m += s2.split(".")[1].length; } catch (e) { }
var result = Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);
if (isNaN(result)) {
result = 0;
}
return result;
}数值相保留几位小数乘
//保留几位小数
ChangeDp: function (val, dp) {
var f_x = parseFloat(val);
if (isNaN(f_x)) {
return 0;
}
var dpVal = Math.pow(10, dp);
f_x = this.numberValueDivide(Math.round(this.numberValueMultiply(f_x, dpVal)),dpVal);
return f_x;
}四舍六入，5看前，奇进偶不进
//四舍六入，5看前，奇进偶不进
NumberValueRevision : function(val,length){
var carry = 0; //存放进位标志
var num,multiple; //num为原浮点数放大multiple倍后的数，multiple为10的length次方
var str = val + ''; //将调用该方法的数字转为字符串
var dot = str.indexOf("."); //找到小数点的位置
//找到要进行舍入的数的位置，手动判断奇偶，满足条件进位标志置为1
if(str.substr(dot+length+1,1)>5){ //>5进位
carry=1;
}else if(str.substr(dot+length+1,1)==5){
//看前一位奇偶
if(str.substr(dot+length,1) && str.substr(dot+length,1)%2==1){
carry=1;
}
if(str.substr(dot+length,1)=="."){
if(str.substr(dot+length-1,1) && str.substr(dot+length-1,1)%2==1){
carry=1;
}
}
}
multiple = Math.pow(10,length); //设置浮点数要扩大的倍数
num = Math.floor(this * multiple) + carry; //去掉舍入位后的所有数，然后加上我们的手动进位数
var result = num/multiple + ''; //将进位后的整数再缩小为原浮点数
/*
* 处理进位后无小数
*/
dot = result.indexOf(".");
if(dot < 0 && length!=0){
result += '.';
dot = result.indexOf(".");
}
/*
* 处理多次进位
*/
var len = result.length - (dot+1);
if(len < length){
for(var i = 0; i < length - len; i++){
result += 0;
}
}
return result;
},校验是否为日期
//校验是否为日期
CheckIsDate: function (s) {
var rg = new RegExp("^((((1[6-9]|[2-9]\\d)\\d{2})-(0?[13578]|1[02])-(0?[1-9]|[12]\d|3[01]))|(((1[6-9]|[2-9]\\d)\\d{2})-(0?[13456789]|1[012])-(0?[1-9]|[12]\\d|30))|(((1[6-9]|[2-9]\\d)\\d{2})-0?2-(0?[1-9]|1\\d|2[0-8]))|(((1[6-9]|[2-9]\\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00))-0?2-29))$");
return this.CheckByRegex(s, rg);
}
CheckByRegex: function (s, rg) {
if (rg) {
if (s && s.match(rg)) {
return true;
}
}
return false;
}日期转字符串
//校验是否为日期
CheckIsDate: function (s) {
var rg = new RegExp("^((((1[6-9]|[2-9]\\d)\\d{2})-(0?[13578]|1[02])-(0?[1-9]|[12]\d|3[01]))|(((1[6-9]|[2-9]\\d)\\d{2})-(0?[13456789]|1[012])-(0?[1-9]|[12]\\d|30))|(((1[6-9]|[2-9]\\d)\\d{2})-0?2-(0?[1-9]|1\\d|2[0-8]))|(((1[6-9]|[2-9]\\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00))-0?2-29))$");
return this.CheckByRegex(s, rg);
}
CheckByRegex: function (s, rg) {
if (rg) {
if (s && s.match(rg)) {
return true;
}
}
return false;
}字符串转日期
stringToDate: function (DateStr, format) {
if (IsEmpty(DateStr)) return "";
if (DateStr instanceof Date) {
return DateStr;
}
if (format == "yyyyMM") {
if (DateStr.length != 6) return "";
DateStr = DateStr.substring(0, 4) + "-" + DateStr.substring(4, 6);
}
var converted = Date.parse(DateStr);
var myDate = new Date(converted);
if (isNaN(myDate)) {
if (DateStr.indexOf(':') > 0 || (!IsEmpty(format) && format.toLowerCase().indexOf("h") > -1)) {
var two = DateStr.split(' ');
if (two.length != 2) {
two = DateStr.split('T');
}
var nowDate = new Date();
if (two.length == 1) {
var tempValue = new Array();
tempValue.push(nowDate.toString("yyyy-MM-dd"));
tempValue.push(two[0]);
two = tempValue;
}
if (two.length != 2) {
return nowDate;
}
var d = two[0].split('-');
var t = two[1].replace("Z", "").split(':');
if (t.length == 3) {
myDate = new Date(d[0], --d[1], d[2], t[0], t[1], t[2]);
}
else if (t.length == 2) {
myDate = new Date(d[0], --d[1], d[2], t[0], t[1], "00");
}
else if (t.length == 1) {
myDate = new Date(d[0], --d[1], d[2], t[0], "00", "00");
}
else if (t.length == 1) {
myDate = new Date(d[0], --d[1], d[2], "00", "00", "00");
}
}
else {
var arys = DateStr.split('-');
switch (arys.length) {
case 1:
if (!IsEmpty(format)) {
var dn = new Date();
if (format == "yyyyMM" && arys[0].length == 6) {
var temMonth = 0;
if (arys[0].substring(4, 5) == "0") {
temMonth = arys[0].substring(5, 6);
}
else {
temMonth = arys[0].substring(4, 6);
}
if (temMonth > 0) {
temMonth = parseInt(temMonth) - 1;
}
myDate = new Date(arys[0].substring(0, 4), temMonth, "01");
}
else if (format.indexOf("y") > -1) {
myDate = new Date(arys[0], 0, "01");
} else if (format.indexOf("M") > -1) {
myDate = new Date(dn.getYear(), --arys[0], "01");
} else if (format.toLowerCase().indexOf("h") > -1) {
myDate = new Date(dn.getYear(), dn.getMonth(), dn.getDate(), arys[0], "00", "00");
} else if (format.indexOf("m") > -1) {
myDate = new Date(dn.getYear(), dn.getMonth(), dn.getDate(), "00", arys[0], "00");
} else if (format.toLowerCase().indexOf("s") > -1) {
myDate = new Date(dn.getYear(), dn.getMonth(), dn.getDate(), "00", "00", arys[0]);
}
}
break;
case 2:
if (CheckIsDate(DateStr + "-01")) {
myDate = new Date(arys[0], --arys[1], "01");
}
else {
return null;
}
break;
default:
if (CheckIsDate(DateStr)) {
myDate = new Date(arys[0], --arys[1], arys[2]);
}
else {
return null;
}
break;
}
}
}
return myDate;
},获取日期的当月第一天
getFirstMonthDay: function (date) {
if (IsEmpty(date)) date = new Date();
return new Date(date.getFullYear(), date.getMonth(), 1);
}获取日期的当月最后一天
getLastMonthDay: function (date) {
if (IsEmpty(date)) date = new Date();
return new Date(date.getFullYear(), date.getMonth() + 1, 0);
}操作时间，加1天，1小时，1分钟
addDay: function (date, num) {
if (date == null) date = new Date();
var newDate = new Date(date.getFullYear(), date.getMonth(), date.getDate(), date.getHours(), date.getMinutes(), date.getSeconds());
newDate.setDate(newDate.getDate() + num);
return newDate;
},
addHour: function (date, num) {
if (date == null) date = new Date();
var newDate = new Date(date.getFullYear(), date.getMonth(), date.getDate(), date.getHours(), date.getMinutes(), date.getSeconds());
newDate.setHours(newDate.getHours() + num);
return newDate;
},
addMinute: function (date, num) {
if (date == null) date = new Date();
var newDate = new Date(date.getFullYear(), date.getMonth(), date.getDate(), date.getHours(), date.getMinutes(), date.getSeconds());
newDate.setMinutes(newDate.getMinutes() + num);
return newDate;
},js判断值是否为空
/**
* 判断值是否为空
* @param {*} value 待判断的值
* @param {Object} [opt] 可选配置
* @param {boolean} [opt.trimNullish=true] 是否把 'null'/'NULL' 视为空
* @param {boolean} [opt.trimBlank=false] 是否把纯空白字符串视为空
* @returns {boolean} 为空返回 true，否则 false
*/
function isEmpty(value, opt = {}) {
const { trimNullish = true, trimBlank = false } = opt;
// 1. null / undefined
if (value == null) return true;
// 2. 字符串特殊处理
if (typeof value === 'string') {
// 2.1 空串
if (value === '') return true;
// 2.2 'null' 串
if (trimNullish && value.toLowerCase() === 'null') return true;
// 2.3 纯空白
if (trimBlank && value.trim() === '') return true;
// 其他字符串一律不为空
return false;
}
// 3. 数组 / 类数组 / Map / Set
if (Array.isArray(value) || value instanceof Map || value instanceof Set) {
return value.length === 0 || value.size === 0;
}
// 4. 普通对象
if (typeof value === 'object') {
return Object.keys(value).length === 0;
}
// 5. 其余情况（数字、布尔、函数、Symbol...）统一视为非空
return false;
}
/* ====== 测试用例 ====== */
console.log(isEmpty(null)); // true
console.log(isEmpty('null')); // true
console.log(isEmpty('NULL')); // true
console.log(isEmpty('')); // true
console.log(isEmpty(' ')); // false（默认）
console.log(isEmpty(' ', {trimBlank: true})); // true
console.log(isEmpty(0)); // false
console.log(isEmpty(false)); // false
console.log(isEmpty(NaN)); // false
console.log(isEmpty([])); // true
console.log(isEmpty({})); // true
console.log(isEmpty(new Map())); // true
console.log(isEmpty(new Set([1]))); // false贡献者
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2026/4/5 03:39
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