Question

Is there a particular reason programmers prefer not to use onClick function in Javascript?

Answer 1

Your question is unclear. What criticism are you referring to? The only thing that springs to mind is the move towards unobtrusive Javascript. The idea is simply to keep your markup as simple as possible and to put all your code in one place. So instead of:

<a id="link" href="..." onclick="open_new_window(); return false;">Open Window</a>

you have:

<a id="link" href="...">Open Window</a>

with something like jQuery:

$(function() {
  $("#link").click(function() {
    open_new_window();
    return false;
  });
});

This is much more maintainable and easier to read.