Interview Questions about DOM in Javascript

1.What is Dom ?

• DOM refers to Document Object Model,It allows javascript to modify,Access,delete elements dynamically.

2.How do you select an elements in DOM ?

• For selecting id document.getElementById("id");
• For selecting class document.getElementByClassName("classname");

1. Difference between getElementById and querySelector

• getElementById simply selects id,if the document has many element it needs to specific element to pointout and select.
• querySelector selects a first element of declared element.

4.Difference between innerHTML and innertext ?

• innerHTML gets HTML contents with tags interpreted
  e.g(it prints along with tag

  happy birthday

  )

• innerText gets only text
  (e.g) it prints only text happy birthday

5.How to create new DOM element ?

• for creating element in dom use document.createElement (e.g) let element = document.createElement("p");

6.How to remove element in DOM ?

• for removing element in DOM use document.getElementByTagName (e.g) document.getElementByTagName("p").remove();

1. How do change CSS style using DOM ?

• By using style property we can access or change CSS style in DOM (e.g) document.getElementByTagName("h1").style.color="red"; document.getElementByTagName("h1").style.color="green";

8.What is Event Delegation and Event Bubbling in DOM ?(TBD)