text-decoration not working for visited state link

Solution 1:

There is a limitation for styling the visited links;

Limits to visited link styles

You will still be able to visually style visited links, but there are now limits on what styles you can use. Only the following properties can be applied to visited links:

color
background-color
border-color (and its sub-properties)
outline-color
The color parts of the fill and stroke properties

Privacy and the :visited selector

text-decoration styling is not permitted due to the user's privacy issues.

Solution 2:

You can done with this jquery addClass.

Demo code

$('a').click(function(){
    $(this).addClass('visited');
});

CSS

.visited {
  color: green;
  text-decoration: line-through;
}

fiddle demo: https://jsfiddle.net/nikhilvkd/7y2fyytw/