var buttons = ['home','about','services','projects','safety','quality','innovations','newsawards','training','contact','home_turnaround','home_piping','home_welding','home_scaffold','home_plant'];
var button_file_type = 'gif';

for (i = 0; i < buttons.length; i++) {
	eval("var " + buttons[i] + " = new Image();");
	eval(buttons[i] + ".src = 'images/nav_" + buttons[i] + "." + button_file_type + "';");
	eval("var " + buttons[i] + "_roll = new Image();");
	eval(buttons[i] + "_roll.src = 'images/nav_" + buttons[i] + "_roll." + button_file_type + "';");
}

function switchon(x,y) {
	document.images[x].src = y.src
}

function switchoff(x,y) {
	document.images[x].src = y.src
}