This Keyword Usage in element And Parameter

Question

I am learning JavaScript event my point is that ' this ' keyword is used for object or global object but in this code this keyword is used in element in function callback parameter why ?

Q1) How we can use 'this' in element onClick event in this code ?

Q2) Secondly sometime i put this keyword in function argument parameter so error generate ' Unexpected Token '.

Kindly help for these two question.

HTML CODE:

<!DOCTYPE HTML>
<html>
<body>
<link type="text/css" rel="stylesheet" href="example.css">

<div class="d1" onclick="highlight(this)">1 
    <div class="d2" onclick="highlight(this)">2
        <div class="d3" onclick="highlight(this)">3
        </div>
    </div>
</div>

<script>
function highlight(elem) {
    elem.style.backgroundColor='yellow'
    alert(elem.className)
    elem.style.backgroundColor = ''
}
</script>

</body>
</html>

Answer 1

Q1) How we can use 'this' in element onClick event in this code ? A)'this' in HTML refers to the HTML element that received the event.in your case the element is 'div'

Q2) Secondly sometime i put this keyword in function argument parameter so error generate 'Unexpected Token'. A) i see 'this' is an implicit param that will be passed automatically when we call a function based on the object , the function call is attached to . so i feel , there will be a conflict b/w function argument's 'this' & implicit 'this'

This Keyword Usage in element And Parameter

Question

1 answers

solution1
0 2021-02-22 11:28:10

This Keyword Usage in element And Parameter

Question

1 answers

solution1 0 2021-02-22 11:28:10

solution1
0 2021-02-22 11:28:10