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

Laravel reads multiple fields from the database and displays them in the view. If the field is empty, it will not be displayed. Is it necessary to add an if judgment to each field?

Laravel reads multiple fields from the database and displays them in the view. If the field is empty, it will not be displayed. Is it necessary to add an if judgment to each field? Like the following: {code...} Is there any other way to write it?

曾经蜡笔没有小新 2017-05-16 16:47:08 0  2  383

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  597

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  1291

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

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  1439

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  1109

How does mysql determine if the data does not exist and then insert it?

When inserting data, can we merge the following requirements into one SQL statement? 1. Determine whether the data exists; 2. There is no insertion; 3. Then query the id field value of the data

怪我咯 2017-07-04 13:43:40 0  4  959

javascript - js determines whether an array is repeated

How does js determine that there are duplicate values ​​in an array object, and delete the duplicate values ​​and keep only one, such as var arr = [{name:'a'},{name:'b'},{name:'c'},{ name:'d'},{name:'a'}] How to compare

typecho 2017-07-05 10:57:12 0  5  1107

javascript - Problems with input positioning in the js front-end of the WeChat applet

1. I wrote a WeChat applet, a Sudoku game, to determine whether it meets the requirements (Sudoku rules) based on the number entered. However, I encountered a problem, how to find the position of the number entered by the user, because the number needs to be converted according to the position. Pass...

天蓬老师 2017-05-19 10:11:40 0  3  753

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

javascript - After editing the js page, I want to perform some operations on the data traversed from the database. For example, if the gender is male, the font will turn red.

After editing the js page, you want to perform some judgment operations on the data traversed from the database. For example, if the gender is male, the font will turn red. Move the mouse over the name to see his profile. Note: The profile exists in the database.

大家讲道理 2017-05-19 10:29:23 0  2  496

How to write in PHP to log in to different pages with different usernames and passwords

As a novice, I originally imagined that when adding a user, I would select the value of value, enter the username and password when logging in, and at the same time determine whether the value of the selected value is 0 or 1. When entering different pages, the name of value saved in the database is ...

TimeLimit 2018-06-17 13:51:17 0  1  1341

php - How to use Lavavel's accessor

Laravel's accessor, how to give a parameter when using toJson. {Code...} {Code...} I hope that when calling the toJson function, I can determine the specific type of $os, and then return the desired field as the value of the url. After searching for a long time, I still can't find the usage. Please ...

某草草 2017-06-05 11:09:29 0  1  759

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  1403

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  1198

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