javascript - How does js determine that the input value is a number, not less than or equal to 0, without using alert, but using red font on the same line to prompt the user

How does js determine that the input value is a number, not less than or equal to 0, and can be a decimal. If the conditions are not met, the user will be prompted in red words after %, TKS!

世界只因有你 2017-06-28 09:27:53 0  4  1451

java - How to modify mybatis if it exists in the database, and add if it does not exist

I want to implement an insert function. Before inserting, it is judged whether there is the same data as the key field in the database. If so, perform the modification operation. If not, perform the insert operation. I would like to ask for advice: Is there any way to make the judgment without doing...

给我你的怀抱 2017-05-17 10:04:15 0  3  598

In JavaScript, except for NaN, are all other variables equal to itself?

How to quickly determine whether the value of a variable val is NaN in javascript? If except for the value of NaN, are all other variables equal to itself, then it is enough to directly judge whether val====val?

学习ing 2017-07-05 10:50:13 0  4  1445

Determine whether the input is a number

def is_number(s):    try:        float(s)        return True    except ValueError:        pass    try:  

P粉325107286 2022-05-13 23:04:37 0  0  1091

Why can't I open it using www.myphp?

<?phpheader('content-type:text/html;charset=utf-8');//The user enters a number, whether it is an odd or even number//Determine whether the number entered by the user is a leap year//The user enters 3 numbers, Output the maximum value $number=$_POST['number'];// echo $number;// if($number%2==1){//...

A-庆装饰设计 2018-02-11 20:37:58 0  4  1293

Determine the difference between values ​​in an object and an array

I have the following array of objects and numbers. How to tell which number in the array does not exist as an id in the object? In the example below, I want 1453. [{id:60,itemName:'MainLocation-1100SuperiorRoad-Cleveland'}{id:1456,itemName:'ThirdLocation-107,West20thStreet,Manhattan-NewYork'}][60,14...

P粉930534280 2023-09-03 19:28:50 0  2  577

Is this okay?

Please let me know if it is not empty and if it is verified, it must be numbers, letters, and underscores, starting with 6 to 10 digits. Can my js part be written like this? Or I should first determine whether it is empty, and then verify the matching characters. Let’s write it like this together, r...

..... 2017-12-02 16:50:45 0  1  1110

javascript - How can I prevent input of type=number from adding plus signs, minus signs and multiple decimal points?

Thank you in advance. I wrote an Input with type = number. Due to business needs, only numbers can be entered in this Input, and the plus and minus signs cannot be entered. I originally wanted to judge the value in the input and manually delete the plus and minus signs and redundant dots, but I foun...

给我你的怀抱 2017-05-16 13:37:46 0  6  1410

Please tell me how to write this

Verify the 18-digit identity number and determine the gender of the identity owner. The rules for the identity number are: ① The first 17 digits are all composed of numbers, and the last digit is a number or character 'X'. The condition for a character ch to be a number is: ch>= '0' && ch...

彦骐 2021-04-28 14:39:06 0  1  1076

How to decompose an integer into the product of prime factors using PHP?

For example, given a number 90, the result is "233*5"; I also got the result myself, but I always think it is too cumbersome. Please ask the experts to see if there are other ideas // judge whether it is a prime number. If it is a prime number, return 1. No returns 0 {code...} //Decompose ...

迷茫 2017-05-16 13:07:43 0  2  613

About converting js string into corresponding variable

Well, this problem has really bothered me for a long time. How to use text characters corresponding to existing variables? For example, there are already two array variables array1 and array2, but I don’t know which one needs to be used. I can only know the name of the corresponding array "arra...

哈哈哈哈。 2019-04-19 15:27:35 0  1  1199

Finally the connection was successful.

<?php// Use the trim function to remove the redundant characters at the front and rear of the password and copy the password to determine whether the passwords entered twice are consistent. if(trim($_POST['password']) != trim($_POST['repassword'])){ exit('The two passwords are inconsistent, pleas...

phpcn_u111636 2018-02-08 21:21:12 0  0  1461

javascript - How to delete an array in redux

This is the initial content in my redux. Now I need to click on a list, for example, click on test 2, and I will delete the list. When I first enter, the content in the status is like this. My judgment in redux is like this, but the result is that the parameters are gone, but the position of the arr...

PHP中文网 2017-06-15 09:22:08 0  2  691

redis信息如何存储

假设每天都会有不少于1000000个唯一标识码进来系统,标识码组成结构是字符串+数字+下划线,形如"ua_124wtybmlo_cfk"。 现在需求是要判断某一个标识码三天内有没有在系统出现过。 如果用有效期是3天的string结构来存...

伊谢尔伦 2017-04-25 09:02:39 0  1  637

c++ - I don't know how much data the server returns. How does PHP's socket_read() receive the complete data?

If the data sent by the server always exceeds the maximum number of bytes that the client can bear to receive at one time, how can the client judge that the received data is complete without performing the socket_read operation? The number of data returned by the server is multiple/n composition. Tr...

淡淡烟草味 2017-05-16 13:09:13 0  1  629

python - mongodb deduplication

1. There is a field in the function that needs to be used to determine whether it is duplicated, such as ownerId. If it exists, it will be discarded. So I used the distinct method, but as the amount of data gradually increased during this period, a problem arose: OperationFailure : distinct too big,...

高洛峰 2017-05-17 10:02:13 0  1  800

thinkphp5 - How does thinkphp operate if there are related arrays in the array, extract the values ​​and add them together?

I have a purchase table in a mall. There are orders in the purchase table. Some orders have the same products as other orders. Then the amount field in the order is the purchase quantity of the product in the order. I want to determine if this order is the same as a certain product. If the ID is the...

仅有的幸福 2017-05-16 13:01:33 0  4  641

python - Why after using requests.get the URL, the response content in .text is in the form of a dictionary, but type it is str

I use anaconda's jupyter to run the code. When I use the requests module to read the web page, I see that the output content is within curly brackets. I judge that it is a dictionary and use the dict function to read the value, but it fails. type() found that its attribute was str. After I used json...

学习ing 2017-06-12 09:21:24 0  3  1002

Theoretical analysis of algorithms that return true or false, based on the study of given probabilities

I want to implement a method that returns true with probability n/m and false with probability (m-n)/m. For example, I want to get true with probability 7/10000. To achieve this goal, I first get a random integer n less than 10000 from the function getRandomIntUnderN. Then, I determine whether n is ...

P粉026665919 2023-09-05 19:57:42 0  1  618

How to eliminate specific repeated characters in a string?

I have a simple string with some repeating characters. Can someone please help me fix the expression below to remove not only duplicate characters but all characters that appear more than 1 time. console.log('aaabbxxstring'.replace(/(.)(?=.*?\1)/g,''));//string I am using lookahead to capture matchi...

P粉354602955 2024-03-31 10:50:33 0  2  515