CODEWITHSUNDEEP
javascriptjqueryscroll
Ilyas karim
Ilyas karim

Reputation: 4812

Add class on html element when it gets visible on screen

I want to add class to the element when it gets visible on screen when scrolling:

<button class='btn btn-default' >
   Hello
</button>

I want to add class to 'btn-default' when the button gets visible on screen after scrolling or when page reloads.

Upvotes: 16

Views: 14436

Answers (3)

Kurenai Kunai
Kurenai Kunai

Reputation: 1902

Try visible selector as in : 

$(window).on('scroll', function(){
    if ($(".btn").is(':visible')){
        $(".btn").addClass("btn-default");
    }
});

Upvotes: 8

Digpal Singh
Digpal Singh

Reputation: 166

Normally you can add and remove class below code but first you add(include) any jquery min js 

Add class: $('.Yourclassname').addClass('addclassname'); 

Remove Class: $('.Yourclassname').removeClass('removeclassname');

Upvotes: -6

Ravimallya
Ravimallya

Reputation: 6600

You've to use jquery $(element).is(':visible') to check whether an element is visible in an HTML document.

JSFiddle

This is the snippet where it will add a class when document ready and when scrolled to the element.

$(function() {
  if ($('#testElement').is(':visible')) {
    $('#testElement').addClass('red');
  }
});
$(window).on('scroll', function() {
  var $elem = $('#testElement1');
  var $window = $(window);

  var docViewTop = $window.scrollTop();
  var docViewBottom = docViewTop + $window.height();
  var elemTop = $elem.offset().top;
  var elemBottom = elemTop + $elem.height();
  if (elemBottom < docViewBottom) {
    alert('hi')
    $('#testElement1').addClass('red');
  }
});
.red {
  background: red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button id="testElement" class="btn btn-default">
  Hello
</button>
<div style="height:400px">Some content</div>
<button id="testElement1" class="btn btn-default">
  Hi
</button>

Upvotes: 1

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