var greeting='Welcome to blog';
(function(){
console.log(greeting); //Output: Welcome to blog
})();
consider above code greeting variable should be global scope, it can access inside the function,
(function(){var greeting = 'Welcome to blog';
console.log(greeting); //Output: Welcome to blog
})();console.log(greeting); //Output:Reference-Error greeting not defined
When you read lessons in this course, you can highlight a single line and save it to your notes. Simply highlight a single line with your mouse (or your finger on mobile) and then a popup will appear asking you to save it to your notes.
You will be able to find these notes in the challenge page by clicking on the Note icon on the top bar, next to the logo. Try it in the next page!
Popular notes will also be shown in yellow highlights which can be easily added to your notes with a single click. And you can also disable those popular highlights from the top right menu.
You can create a string in JavaScript by simply using the double quotes (") or single quotes (').
Here's an example:
"This is a string";'this is another string!'
There is no difference between using a double quote or a single quote. They are exactly the same. Both of these strings do not support interpolation (which means interpolating a variable inside of them). String interpolation will be covered in a future lesson.
Basic String properties
the .length property is used to return the length of the string.
Here's an example of getting the length of "Nice!":
"Nice!".length;//5
We will learn about variables later in this course, but assuming you have a variable called description, here's how you'd get its length:
description.length;
Basic String methods
Here are some common methods that you can call on strings:
.includes(searchString)
This method returns true when the searchString is included inside the parent string. For example:
This will return a new string that has all of its characters in upper case:
"hello".toUpperCase();// "HELLO";
.toLowerCase()
This will return a new string that has all of its characters in lower case:
"NICe".toLowerCase();// "nice";
Hint: Stuck? Feel free to use CodeToGo to search for common use cases
A note on tests & sample usage
On the left of the screen, you've got tests running your code. And in your editor, you will almost always have some sample usage code.
functionsum(a, b){return a + b;}//sample usagesum(1,3);
The sample usage code is meant to illustrate how your code will be used. However keep in mind that we will take the function that you wrote, and call it against several other possibilities to make sure that you've got the correct answer. Feel free to use console.log() for the parameters of the function to see what kind of tests we're running.
So even though the sample usage is sum(1, 3), we run more tests in the background with several values. We also often run it with edge case values such as sum(0, 0). All of this simulates a real Test Driven Development environment.
A note on console.log
When solving challenges feel free to add:
console.log(variable_or_expression)
to see its result in the console on the bottom left.
You can also use it to better understand theteststhat you're trying to pass.
Function ibarat menulis resepi atau rukun. Contoh, senaraikan rukun iman?
rukunIman
percaya kepada Allah,
percaya kepada Rasul,
percaya kepada Malaikat,
percaya kepada Al-kitab,
percaya kepada hari akhirat,
percaya kepada qada dan qadar,
Bila ditulis dalam kaedah javascript ia akan menjadi seperti ini
function rukunIman(){
percaya kepada Allah;
percaya kepada Rasul;
percaya kepada Malaikat;
percaya kepada Al-kitab;
percaya kepada hari akhirat;
percaya kepada qada dan qadar;
}
..
Atau function lebih kepada buat seketul sandwich
function makeSandwich(){
Get one slice of bread;
Add turkey;
Put a slice of bread on top;
}
..
Macam mana kalau nak buat option add turkey kepada benda atau isi lain?
..
function makeSandwich(filling){
Get one slice of bread;
Add filling;
Put a slice of bread on top;
}
makeSandwich('burger')
..
ibaratnya, pelanggan datang dan mintak sandwich isi burger, jadi kita beri option kepada pelanggan untuk pilih isi apa.. refer filling
Function memberi peranan atau jawatan kepada sesuatu
function sayHiTo(peserta){
console.log('hai', peserta);
}
sayHiTo ('muhaza')
..
Secara automatik muhaza akan diberi jawatan peserta atau peserta itu bernama muhaza
The Array object has many properties and methods which help developers to handle arrays easily and efficiently. You can get the value of a property by specifying arrayname.property and the output of a method by specifying arrayname.method().
length property --> If you want to know the number of elements in an array, you can use the length property.
prototype property --> If you want to add new properties and methods, you can use the prototype property.
reverse method --> You can reverse the order of items in an array using reverse method.
sort method --> You can sort the items in an array using sort method.
pop method --> You can remove the last item of an array using pop method.
shift method --> You can remove the first item of an array using shift method.
push method --> You can add a value as the last item of array.
<html><head><title>Arrays!!!</title><script type="text/javascript">var students =newArray("John", "Ann", "Aaron", "Edwin", "Elizabeth");
Array.prototype.displayItems=function(){
for (i=0;i<this.length;i++){
document.write(this[i] +"<br />");
}
}
document.write("students array<br />");
students.displayItems();
document.write("<br />The number of items in students array is "+ students.length +"<br />");
document.write("<br />The SORTED students array<br />");
students.sort();
students.displayItems();
document.write("<br />The REVERSED students array<br />");
students.reverse();
students.displayItems();
document.write("<br />THE students array after REMOVING the LAST item<br />");
students.pop();
students.displayItems();
document.write("<br />THE students array after PUSH<br />");
students.push("New Stuff");
students.displayItems();
</script></head><body></body></html>
<h2 class="title">This text will change</h2> <script> var x = document.getElementsByClassName("title"); var i; for (i = 0; i < x.length; i++) { x[i].innerHTML= "This text has changed"; } </script>
