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

document.write('<form name="form" target="_blank">');
document.write('<select name="site" size=1>');
document.write('<option value="">Select a Country...</option>');
document.write('<option value="marriagelaws/england.html">England</option>');
document.write('<option value="marriagelaws/france.html">France</option>');
document.write('<option value="marriagelaws/northernireland.html">Northern Ireland</option>');
document.write('<option value="marriagelaws/scotland.html">Scotland</option>');
document.write('<option value="marriagelaws/wales.html">Wales</option>');
document.write('</select>');
document.write(' <input type=button value="Submit" onClick="javascript:formHandler()">');
document.write('</form>');