function cambia(form) {
if (form.pais.value == "us") {
document.getElementById('estado').innerHTML='Estado:';
document.getElementById('estados').innerHTML='<select name="estado"><option value="">Elige tu estado</option><option value="Alabama">Alabama</option><option value="Alaska">Alaska</option><option value="Alberta">Alberta</option><option value="Arizona">Arizona</option><option value="Arkansas">Arkansas</option><option value="British Columbia">British Columbia</option><option value="California">California</option><option value="Colorado">Colorado</option><option value="Connecticut">Connecticut</option><option value="Delaware">Delaware</option><option value="District Of Columbia">District Of Columbia</option><option value="Florida">Florida</option><option value="Georgia">Georgia</option><option value="Hawaii">Hawaii</option><option value="Idaho">Idaho</option><option value="Illinois">Illinois</option><option value="Indiana">Indiana</option><option value="Iowa">Iowa</option><option value="Kansas">Kansas</option><option value="Kentucky">Kentucky</option><option value="Louisiana">Louisiana</option><option value="Maine">Maine</option><option value="Manitoba">Manitoba</option><option value="Maryland">Maryland</option><option value="Massachusetts">Massachusetts</option><option value="Michigan">Michigan</option><option value="Minnesota">Minnesota</option><option value="Mississippi">Mississippi</option><option value="Missouri">Missouri</option><option value="Montana">Montana</option><option value="Nebraska">Nebraska</option><option value="Nevada">Nevada</option><option value="New Brunswick">New Brunswick</option><option value="New Hampshire">New Hampshire</option><option value="New Jersey">New Jersey</option><option value="New Mexico">New Mexico</option><option value="New York">New York</option><option value="Newfoundland">Newfoundland</option><option value="North Carolina">North Carolina</option><option value="North Dakota">North Dakota</option><option value="Northern Mariana Is">Northern Mariana Is</option><option value="Northwest Territories">Northwest Territories</option><option value="Nova Scotia">Nova Scotia</option><option value="Ohio">Ohio</option><option value="Oklahoma">Oklahoma</option><option value="Ontario">Ontario</option><option value="Oregon">Oregon</option><option value="Palau">Palau</option><option value="Pennsylvania">Pennsylvania</option><option value="Prince Edward Island">Prince Edward Island</option><option value="Province du Quebec">Province du Quebec</option><option value="Puerto Rico">Puerto Rico</option><option value="Rhode Island">Rhode Island</option><option value="Saskatchewan">Saskatchewan</option><option value="South Carolina">South Carolina</option><option value="South Dakota">South Dakota</option><option value="Tennessee">Tennessee</option><option value="Texas">Texas</option><option value="Utah">Utah</option><option value="Vermont">Vermont</option><option value="Virgin Islands">Virgin Islands</option><option value="Virginia">Virginia</option><option value="Washington">Washington</option><option value="West Virginia">West Virginia</option><option value="Wisconsin">Wisconsin</option><option value="Wyoming">Wyoming</option><option value="Yukon Territory">Yukon Territory</option></select>';
} else {
document.getElementById('estado').innerHTML='';
document.getElementById('estados').innerHTML='';
}
}