function formHandler(){
var URL = document.form.site.options[document.form.site.selectedIndex].value;
window.location.href = URL;
}

document.write('<form name="form">');
document.write('<select name="site" class=menubox size=1 onChange="javascript:formHandler()">');
document.write('<option value="index.htm">...Menu...');
document.write('<option value="javascript:history.go(-1);">...Previous Page...');
document.write('<option value="incomelevels.htm">Income Levels');
document.write('<option value="labourforce.htm">Labour Force');
document.write('<option value="urbanpopulation.htm">Urban Population');
document.write('<option value="regionalpopulation.htm">Regional Population');
document.write('<option value="populationprojections.htm">Population Projections');
document.write('<option value="trafficcounts.htm">Traffic Counts');
document.write('<option value="index.htm">Intro');
document.write('</select>');
document.write('</form>');