Html upload input type="file" only allows uploading image files

... <from action="" enctype="multipart/form-data" method="post"> <a> <span>修改头像</span> <input type="file" id="fileUp" accept="image/png,image/jpeg"> </a> </from> var fileM=document.querySelector("#fileUp"); $("#fileUp").on("change",function() { //获取...


How to "destroy" ADC noise

... (一): The way noise passes Data converter has become an important bridge connecting the analog and digital world, and is also an indispensable important component in the industrial field. Since the global economic recovery in 2011, the expanding industrial electronics market has brought...


Introduction of Energy Storage Converter PCS and Virtual Synchronizer VSG

... PCS Introduction: The energy storage converter (PCS) is also a DC/AC three-phase inverter, which has the same topology as the wind power converter and the photovoltaic inverter, but the PCS can charge and discharge the energy. For several types of products, the hardware difference is...


Basic security of the CentOS7_ account

... annotate unnecessary users and user groups [[email protected] ~]# vim /etc/passwd //Edit account configuration file Root:x:0:0:root:/root:/bin/bash Bin:x:1:1:bin:/bin:/sbin/nologin Daemon:x:2:2:daemon:/sbin:/sbin/nologin #adm:x:3:4:adm:/var/adm:/sbin/nologin //Add "#" to the username to...


What is the daily scouring? How to make money? How to get a daily invitation code?

... [Daily Yitao] Give you 4 reasons first. Do you think it will be a pyramid scheme company? Top investment background: Daily Optimum is a leading enterprise in Tencent. The daily scouring is a new social e-commerce gourmet entrepreneurial platform based on daily optimism. 强的公司力量: The...


"Assembly Language" Notes - Chapter 1 Basics

... 机器语言 机语言 is a collection of machine instructions. The machine instructions of a computer are a list of binary digits. The computer turns it into a series of high and low levels to drive the computer's electronics to operate. Each microprocessor has its own set of machine instructions,...


[AtCoder1981] Shorten Diameter

... # include <cstdio> # include <vector> using namespace std ; const int MAXN = 2005 ; int N , K ; vector < int > adj [ MAXN ] ; int dep [ MAXN ] , fa [ MAXN ] , cnt ; void dfs ( int u , int f , int lim ) { for ( int i = 0 ; i < ( int ) adj [ u ] . size ( ) ; i ++ ) {...


The problem of output pointers in C language

... #include<stdio.h> Void main(void){ Char *p; Char i = 'c'; p = &i; Printf("The value of i is: %c\n", i); Printf("i's address is: %p\n", &i); Printf("The result of outputting p as a pointer is: %p\n", p); } 分析: The above results show that when the value of the pointer is...


The second method of seeking (fast power problem)

... 快幂问题 (see a^b) We all know that when the index is even, for a**b, it can be changed to (a**2)* *(b/2). When the index is odd, for a**b, it can be reduced to a*(a**(b-1)), and then it can be reduced to a*((a**2)**(( B-1)/2)) So we can know that if b is an odd number, then b is reduced by...


Shenzhen has an annual salary of 550,000 and Xi'an 200,000. Which city do you choose?

... Recently contacted a buddy of a well-known large factory in Shenzhen, is a senior development engineer, the income is also good, the annual salary of 550,000. Just a good company in Shenzhen needed such a technical talent, he chatted with him, but he refused, because he wanted to return...