Javascript basicos para cualquier formulario

function trim(cadena)
{
for(i=0 ; i < cadena .length; )
{
if(cadena.charAt(i)==" ")
cadena=cadena.substring(i+1, cadena.length);
else
break;
}

for(i=cadena.length-1; i>=0; i=cadena.length-1)
{
if(cadena.charAt(i)==" ")
cadena=cadena.substring(0,i);
else
break;
}

return cadena;
}

function aMayuscula(form){
form.txtUsuari.value = form.txtUsuari.value.toUpperCase();
}

function aMinuscula(form,texto){
form.texto.value = form.texto.value.toLowerCase();
}

function noNumbers(e)
{
var keynum;
var keychar;
var numcheck;

if(window.event) // IE
{
keynum = e.keyCode;
}
else if(e.which) // Netscape/Firefox/Opera
{
keynum = e.which;
}
keychar = String.fromCharCode(keynum);
numcheck = /\d/;
return !numcheck.test(keychar);
}

function EnterUsuari(e){

if (getKeyCode(e)==13)
document.frmValidar.submit();
}
function getKeyCode(e){
e= (window.event)? event : e;
intKey = (e.keyCode)? e.keyCode: e.charCode;
return intKey;
}
function Enter(e){

if (getKeyCode(e)==13)
if( trim(document.frmValidar.txtUsuari.value) == '')
{ document.frmValidar.txtUsuari.value = '';
alert('Debe ingresar un codigo de usuario');
}
else
document.frmValidar.txtPasswd.focus();
}

function btnValidar(){
document.frmValidar.submit();
}