Código HTML:
Ver original<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<script language="javascript">
function padNmb(nStr, nLen){
var sRes = String(nStr);
var sCeros = "0000000000";
return sCeros.substr(0, nLen - sRes.length) + sRes;
}
function secsToTime(time) {
var hora = Math.floor(time / 3600);
var min = Math.floor ((time - (hora * 3600)) / 60 );
return padNmb(hor, 2) + ":" + padNmb(min, 2);
}
function stringToSeconds(time_1, time_2) {
return (Number(time_1) * 3600) + (Number(time_2) * 60);
}
function substractTimes(hr_1, min_1, hr_2, min_2) {
var secs1 = stringToSeconds(hr_1, min_1);
var secs2 = stringToSeconds(hr_2, min_2);
var secsDif = secs1 - secs2;
return secsToTime(secsDif);
}
function calcHr(){
with (document.frm)
uf.value = substractTimes(hr_2.value, min_2.value, hr_1.value, min_1.value);
}
<form id="frm" name="frm"> <table width="350" align="center"> <td width="157"><div align="right">Hora Inicio:
</div></td> <input name="hr_1" type="text" id="hr_1" size="5" /> <td width="90"><div align="left"> <input name="min_1" type="text" id="min_1" size="5" /> <input name="hr_2" type="text" id="hr_2" size="5" /> :
<input name="min_2" type="text" id="min_2" size="5" />
<input type="button" name="Calcular" value="Calcular" onclick="calcHr()" /> <td colspan="2"><div align="center"> <input name="uf" type="text" id="uf" />