Without knowing the internals, it seems you're trying to call changeoption(name, value), you can do this entirely in jQuery, like this:
$("form select[onchange^='change_option']")
.addClass('link_fix3')
.change(function() {
changeoption(this.name, $(this).val());
});
Though with more details, this can probably be even simpler, for example is giving the <select> a class initially an option? That would make the selector much cleaner, then you can leave the initial onchange attribute off completely...you have to admit this looks prettier :)
<select name="SELECT___100E___7" class="link_fix3">
Script like this:
$("form select.link_fix3").change(function() {
changeoption(this.name, $(this).val());
});
If you post what your changeoption function looks like, I could improve the answer to show additional simplifications, if any of these options I'm offering are do-able...I know the programmers control over markup varies widely, so let us know what options you do have.