<p class="hello">
</p>
<script>
//function 1
// let x = myFunction(20,30)
function myFunction(a,b){
return a*b ;
}
document.getElementsByClassName("hello").innerHTML = myFunction(2,3);
</script>
i tried to change text using function, by getelementbyid it's working properly but why it is not working with getelementsbyclass, is there any rule for this ?