For modern browsers:

var checkedValue = document.querySelector('.messageCheckbox:checked').value; 

By using jQuery:

var checkedValue = $('.messageCheckbox:checked').val(); 

Pure javascript without jQuery:

var checkedValue = null; var inputElements = document.getElementsByTagName('input'); for(var i=0; inputElements[i]; ++i){ if(inputElements[i].className==="messageCheckbox" && inputElements[i].checked){ checkedValue = inputElements[i].value; break; } } 

For modern browsers:

var checkedValue = document.querySelector('.messageCheckbox:checked').value; 

By using jQuery:

var checkedValue = $('.messageCheckbox:checked').val(); 

Pure javascript without jQuery:

var checkedValue = null; var inputElements = document.getElementsByClassName('messageCheckbox'); for(var i=0; inputElements[i]; ++i){ if(inputElements[i].checked){ checkedValue = inputElements[i].value; break; } }