Edit in JSFiddle

$("#btn").click(function() {
  $(this).toggleClass("highlight")
  $(this).text() === 'Add Highlight'
    ? $(this).text('Remove Highlight')
    : $(this).text('Add Highlight')
})
<button id="btn">
  Add Highlight
</button>

<button id="btn2">
  Add Highlight
</button>

              

External resources loaded into this fiddle: