//Valida que solamente la cadena de entrada
//contenga sólo números
function OnlyNumbers(e) {

    var keynum;
    var keychar;
    var numcheck;

    if (e.keyCode) // IE/Firefox
    {
        keynum = e.keyCode;
    }
    else
        if (e.which) // Netscape/Firefox/Opera
    {
        keynum = e.which;
    }


    if (keynum == 8) {
        return true;
    }
    if (keynum == 9) {
        return true;
    }

    keychar = String.fromCharCode(keynum);
    numcheck = /\d/;
    return numcheck.test(keychar);
}


function OnlyText(e) {

    var keynum;
    var keychar;
    var numcheck;

    if (e.keyCode) // IE/Firefox
    {
        keynum = e.keyCode;
    }
    else
        if (e.which) // Netscape/Firefox/Opera
    {
        keynum = e.which;
    }
  
    if ((keynum > 32 && keynum < 48) || (keynum > 57 && keynum < 65) || (keynum > 90 && keynum < 97) || (keynum >= 48 && keynum <= 57) || keynum == 191) {
        
        return false;
    }
}

function OnlyMoney(e) {

    var keynum;
    var keychar;
    var numcheck;

    if (e.keyCode) // IE/Firefox
    {
        keynum = e.keyCode;
    }
    else
        if (e.which) // Netscape/Firefox/Opera
    {
        keynum = e.which;
    }

    if (keynum == 8 || keynum == 9 || keynum == 44|| (keynum >= 48 && keynum <= 57)) {
        return true;
    } 
   
    keychar = String.fromCharCode(keynum);
    numcheck = /\d/;
    return numcheck.test(keychar);
}


//Remueve aquéllos caracteres inválidos que pueden
//considerarse un request peligroso, esto se utiliza
//con el fin de evitar por ejemplo inyección de sql.
function RemoveDangerousRequestText(e) {

    var keynum;
    var keychar;
    var numcheck;

    if (e.keyCode) // IE/Firefox
    {
        keynum = e.keyCode;
    }
    else
        if (e.which) // Netscape/Firefox/Opera
    {
        keynum = e.which;
    }
   
    if ((keynum >= 60 && keynum <= 63) || keynum == 91 || keynum == 93 || (keynum > 32 && keynum <= 41) || keynum == 47 || keynum == 161 || keynum == 95 || keynum == 123 || keynum == 44 || keynum ==125 || keynum == 46 || keynum == 58) {

        return false;
    }
}