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Sujith V S
Sujith V S

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JavaScript Crash Notes

Datatypes:
Number type, String type, Boolean type

innerText = Take all the text inside an element.
innerHTML = Takes all the text and child element.

Onclick

<button>Increment</button>

Why === instead of == ?
eg 100 == "100" - double equal ignores the fact that one is number and other is string and return the value to True. === strictly checks it, if both the values are of diff data types, then === wont return it to true.

querySelector - with this we can select element by its id or class or by the element name.
ed: document.querySelector("#id")

Array
featuredPost.length - length property will return length of an array.
cards.push(6) - push method pushes a value to the array.
To acces a value in an array = arrayName.keyName

JS Random number:
let randomNumber = Math.floor(Math.random()*13) + 1

Event Listner
inputBtn.addEventListner("click", function(){
console.log(".......")
})

const - cannot be reassigned
if we want to reassign use let, else use const.

creating element
ulEl.innerHTML += "<li>" + myLeads[i] + "</li>"
const li = document.createElement("li")
li.textContent = myLeads[i]
ulEl.append(li)

<a href='" + myLeads[i] + "'>" + myLeads[i] + "</a>
This is how to put a link inside a in innerhtml purpose.

Template strings-
eg:myName ={$variable}``

LOCAL STORAGE : -
localStorage.setItem("names", "MY LOVE")
console.log(localStorage.getItem("names"))
localStorage.clear()

To convert it to string and to convert it to js object.

`
myLeads = JSON.parse(myLeads)
myLeads.push("ajith")
console.log(myLeads)
myLeads = JSON.stringify(myLeads)
console.log(typeof myLeads)
`

Falsy value JS:
false
0
""
null = how we as a developer signalizes emptiness
undefined = how js signalizes emptiness
NaN

In JavaScript, undefined is a type, whereas null an object. In undefined a variable declared, but no value has been assigned. Whereas, null in JavaScript is an assignment value. You can assign it to a variable.

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