how get alert on click of a button jquery code example

Example 1: jquery click event

$('#selector').on('click',function(){
    //Your code here
});

Example 2: onclick event in jquery ajac

$('a').click(function(){
$.ajax({
type: "POST",
url: "mysimplepage.php",
async: true,
data: { logDownload: true, file: $(this).attr("name") }
});
return false;
});