JavaScript console.log()
What is the console.log() Method
1] console.log() is a built-in function.
2] console.log() is allows to output Message .
3] And value to the console.
4] console.log() use for debugging & understanding code.
5] log() method writes a message to the console.
6] log() method useful to testing purposes.
7] console.log() method is javaScript logs message or data to console.
8] console.log() debugging by displaying object properties, program flow or variable value .
9] console.log() method supported all browsers.
Example :- chrome, internet explore, Edge , Firefox , Safari, Opera, ext.
Console.log();
Syntax
console.log(" ");
Example :-
JavaScript code -
console.log
(" Welcome learn programming language to
link-https://webdesigningtheory.blogspot.com/");
Output :-
Data Type :-
1] String data type
Example :-
JavaScript code -
let str =
"Welcome to learn programming language
link-https://webdesigningtheory.blogspot.com/";
console.log(str);
Output :-
2] number data type
Example :-
JavaScript code -
let A =7;
console.log( A);
Output :-
3] Boolean data type
1] Boolean datatype returns either two value - true or false .
2] boolean used object, condition, variable, expressions etc.
3] boolean terms of True or False value.
Example :-
JavaScript code -
function one(){
console.log(Boolean(20));
}
one();
Output
Example :-
JavaScript code -
function one(){
console.log(Boolean(""));
}
one();
Output :-
4] undefined data type
1] undefined value is global read only variable .
2] undefined is type of primitive type.
Example :-
JavaScript code -
let myvalue;
if (typeof myvalue==="undefined"){
console.log("myvalue is undefined");
}
else {
console.log("myvalue is defined");
}
Output
5] null data type
Example :-
JavaScript code -
const value =null;
if(value)
{
console.log("value is not null");
}
else {
console.log("value is null ");
}
Output:-
