How do you use not null in JavaScript?

Posted on by Muna Meyer

How do you use not null in JavaScript?

You can easily check if a variable Is Null or Not Null in JavaScript by applying simple if-else condition to the given variable….

  1. If my_var is undefined then the condition will execute.
  2. If my_var is 0 then the condition will execute.
  3. If my_var is ” (empty string) then the condition will execute.
  4. …

How can I add mobile number validation?

$/; if (filter. test(phoneNumber)) { if(phoneNumber. length==10){ var validate = true; } else { alert(‘Please put 10 digit mobile number’); var validate = false; } } else { alert(‘Not a valid number’); var validate = false; } if(validate){ //number is equal to 10 digit or number is not string enter code here… }

How do I validate a phone number in HTML?

Using Simple Mobile Number Validation Regex in Pattern [789][0-9]{9} We can also use simple HTML pattern for mobile like first we make it mandate that initial number should be started with 7 or 8 or 9 and then it followed by a series of number up to 9 digits.

Is not empty JavaScript?

Use the === Operator to Check if the String Is Empty in JavaScript. We can use the strict equality operator ( === ) to check whether a string is empty or not. The comparison data===”” will only return true if the data type of the value is a string, and it is also empty; otherwise, return false .

How check file is empty or not in JavaScript?

How to check input file is empty or not using JavaScript/jQuery?

  1. Approach 1: Use element. files. length property to check file is selected or not.
  2. Example: This example implements the above approach.
  3. Output:
  4. Approach 2: Use element. files.
  5. Example: This example implements the above approach.
  6. Output:

IS NOT NULL check JavaScript?

Check if a Variable is Not NULL in JavaScript

  • Use the strict inequality (! ==) operator to check if a variable is not null – myVar !==
  • This means that if you compare null with any other type, the strict inequality (!
  • The falsy values in JavaScript are: false , 0 , “” , null , undefined , NaN .

IS null condition in JavaScript?

The JavaScript specification says about null : null is a primitive value that represents the intentional absence of any object value. If you see null (either assigned to a variable or returned by a function), then at that place should have been an object, but for some reason, an object wasn’t created.

Is number validation in Javascript?

We have used isNaN() function for validation of the textfield for numeric value only. Text-field data is passed in the function and if passed data is number then isNan() returns true and if data is not number or combination of both number and alphabets then it returns false.