Declare Variable in Java-Script

Declare Variable in Java-Script To declare variable in java-script. The term " var " is used. Syntax: var variable name Code: < head> < title> < /head> < body> < /body> < script> var number=100 document.write(" The number is " + number) < /script> < /html> Output: The number is 100 What is concatenation in Java-script? It is used for combining two or more strings to create a new string. It allows you to join text or string variables to create a new string. In java-script the you can concatenate string using the " + " operator. Here is the example to how's it woks: < !DOCTYPE html> < head> < title> < /head> < body> < /body> < script> var num1=10 var num2=20 document.write(" First number is " +num1+ " Second number is " +num2) < /script> < /html> In this example num1 and num2 are concatenated. Output: First number is 10 Second number is 20. How to take data from the user in Java-script? To take data from the user the term "prompt" is used. Code: < head> < title> < /head> < body> < /body> < script> var num1=prompt("enter first number") var num2=prompt("enter second number") document.write(" First number is " +num1+ " Second number is " +num2) < /script> < /html> This code will take 2 numbers from the user.