function Atras()
  {
		history.go(1);
		return false;
  }	
  
	//funcion para aceptar solo valores numericos y letras en el textbox
	function acceptNumLetra(e)
	{
	
		tecla = (document.all) ? e.keyCode : e.which; 
		
		if (tecla==8) return true; //Tecla de retroceso
		if (tecla==46) return true; //Tecla de punto
		if (tecla==32) return true; //Tecla de espacio
		if (tecla==13) return true; //Tecla de Enter
		if (tecla==64) return true; //Tecla de Arroba @
		if (tecla==241 || tecla==209) return true; //241 es la Ñ y 209 es la ñ
		
		//patron =/[A-Za-z\s]/; // Solo acepta letras 
		//patron = /\d/; Solo acepta números 
		patron = /\w/; //Acepta números y letras 
		//patron = /\D/; No acepta números 
		te = String.fromCharCode(tecla); 
		return patron.test(te); 
	} 


	var nav4 = window.Event ? true : false;
	function TipoSangre(evt)
	{ 
		var key = nav4 ? evt.which : evt.keyCode;
		return ( (key >= 97 && key <= 122) || (key >= 65 && key <= 90) || (key == 8) || (key == 32) || (key == 13) || (key == 64) || (key == 45) || (key == 43));
	}
	

	var nav4 = window.Event ? true : false;
	function acceptCaracteres(evt)
	{ 
		var key = nav4 ? evt.which : evt.keyCode;
		return ( (key >= 97 && key <= 122) || (key >= 65 && key <= 90) || (key == 8) || (key == 32) || (key == 13) || (key == 64));
	}
	
	
		//funcion para aceptar solo valores numericos en el textbox
	var nav4 = window.Event ? true : false;
	function acceptNum(evt)
	{ 
		var key = nav4 ? evt.which : evt.keyCode;
		return (key <= 13 || (key >= 48 && key <= 57));
	}
	
//Funcion para deshabilitar boton derecho del mouse
	function clickIE()
	{
	if (document.all) 
	{
	alert('Sistema de Solicitudes de Acceso a la Información');
	return false;
	}
	}

	function clickNS(e){
	if (document.layers||(document.getElementById&&!document.all)){
	if (e.which==2||e.which==3){
	alert('Sistema de Solicitudes Acceso a la Información');
	return false;
	}
	}
	}

	if (document.layers){
	document.captureEvents(Event.MOUSEDOWN);
	document.onmousedown=clickNS;
	}else{
	document.onmouseup=clickNS;
	document.oncontextmenu=clickIE;
	}
//

//Maximizar ventana
function maximiza_ventana()
{ 
resizeTo(screen.width, screen.height) 
moveTo(0, 0); 
}


//Reloj Digital
function clock() 
{
	if (!document.layers && !document.all) 
		return;
		
		
	var digital = new Date();
	var hours = digital.getHours();
	var minutes = digital.getMinutes();
	var seconds = digital.getSeconds();
	var amOrPm = "AM";
	if (hours > 11) amOrPm = "PM";
	if (hours > 12) hours = hours - 12;
	if (hours == 0) hours = 12;
	if (minutes <= 9) minutes = "0" + minutes;
	if (seconds <= 9) seconds = "0" + seconds;
	dispTime = hours + ":" + minutes + ":" + seconds + " " + amOrPm;
	
	if (document.layers)
	{
		document.layers.pendule.document.write(dispTime);
		document.layers.pendule.document.close();
	}
	else
		if (document.all)
			pendule.innerHTML = dispTime;

	setTimeout("clock()", 1000);
}
//

//EFECTO DE MENU

    var desactivado= new Image();
    var activado=new Image();
   
   
    function activar(nombreImagen) {
      if (document.images) {
        document[nombreImagen].src=activado.src;
        }
    }
    function desactivar(nombreImagen) {
      if (document.images) {
        document[nombreImagen].src=desactivado.src; }
    }
    
    function efecto(nombreImagen,imagen, accion)
    {
    if (document.images) {
      activado.src="Images/Botones/"+imagen;
      desactivado.src="Images/Botones/"+imagen;
    }
    
    if (accion==1){
        activar(nombreImagen);
        }
          else
        {
        desactivar(nombreImagen); 
        }
    }
    
    
    function imprimeformato()
	{
		bV = parseInt(navigator.appVersion);
		if (bV >= 4) window.print();
	}
	
	
	var reOneOrMoreDigits = /[\d+]/;
    var reNoDigits = /[^\d]/gi;
    function doMask(textBox) 
    {
		var keyCode = event.which ? event.which : event.keyCode;
        // enter, backspace, delete and tab keys are allowed thru
        if(keyCode == 13 || keyCode == 8 || keyCode == 9 || keyCode == 46) return true;
        // get character from keyCode....dealing with the "Numeric KeyPad" 
        // keyCodes so that it can be used
        var keyCharacter = cleanKeyCode(keyCode);
        // grab the textBox value and the mask
        var val = textBox.value;
        var mask = textBox.mask;
        // simple Regex to check if key is a digit
        if(reOneOrMoreDigits.test(keyCharacter) == false)
			return false;
        // get value minus any masking by removing all non-numerics
        val = val.replace(reNoDigits,'');                             
        // add current keystroke
        val += keyCharacter;
        // mask it...val holds the existing TextBox.value + the current keystroke
        textBox.value = val.maskValue(mask);
        setCaretAtEnd(textBox);
        return false;
    }

    // puts starting chars in field
    function onFocusMask(textBox) 
    {
		var val = textBox.value;
        var mask = textBox.mask;
        if(val.length == 0 || val == null) 
        {
			var i = mask.indexOf('#');
            textBox.value = mask.substring(0,i);
        }
        setCaretAtEnd(textBox);
        // set just in case.
        textBox.maxlength = mask.length;
    }

    // blank field if no digits entered

    function onBlurMask(textBox) 
    {
        var val = textBox.value;
        // if no digits....nada entered.....blank it.
        if(reOneOrMoreDigits.test(val) == false) 
        {
			textBox.value = '';
        }
    }

    String.prototype.maskValue = function(mask) 
    {
         var retVal = mask;
         var val = this;
         //loop thru mask and replace #'s with current value one at a time
         // better way of doing this ???
         for(var i=0;i<val.length;i++) 
         {
			retVal = retVal.replace(/#/i, val.charAt(i));
         }
         // get rid of rest of #'s
         retVal = retVal.replace(/#/gi, "");
         return retVal;
    }
    // The Numeric KeyPad returns keyCodes that ain't all that workable.
    //
    // ie: KeyPad '1' returns keyCode 97 which String.fromCharCode converts to an 'a'.
    //
    // This cheesy way allows the Numeric KeyPad to be used
    function cleanKeyCode(key)
    {
		switch(key)
        {
			case 96: return "0"; break;
            case 97: return "1"; break;
            case 98: return "2"; break;
            case 99: return "3"; break;
            case 100: return "4"; break;
            case 101: return "5"; break;
            case 102: return "6"; break;
            case 103: return "7"; break;
            case 104: return "8"; break;
            case 105: return "9"; break;
            default: return String.fromCharCode(key); break;
        }
    }
                                   
    // From:
    function setCaretAtEnd (field) 
    {
		if (field.createTextRange) 
		{
			var r = field.createTextRange();
            r.moveStart('character', field.value.length);
            r.collapse();
            r.select();
         }
     }


	//Pago
	function Pago(field, cambio_field, total) 
	{
		if (window.event.keyCode != "13")
		{
			field.value = parseFloat(field.value);
			
			if (isNaN(field.value))
				field.value = ''
			
			var total = parseFloat(document.getElementById(total).value);
			var cambio = field.value - total; 
			if ( cambio >= 0 )
			{
				document.getElementById(cambio_field).value = cambio ;
			}
			else
			{
				document.getElementById(cambio_field).value = '0' ;
			}
		}
		else
		{
			document.getElementById('btn_Pagar').focus();
		}
	}
	
	
	//Muestra las ventanas de ayuda
	function muestra_ayuda(element,imagen,ancho,alto) 
	{
		if (typeof element == "string")
			element = document.getElementById(element)
			
		if (!element) return { top:0,left:0 };
			
		var y = 0;
		var x = 0;
			
		x = window.event.clientX 
		y = window.event.clientY 

		/*x += window.document.body.scrollLeft; 
		y += window.document.body.scrollTop; */

		my_window = window.open("","Ayuda","resizable=0,toolbar=no,status=0,width="+ancho+",height="+alto+",menubar=no,left=x,top=y,position=absolute");
		my_window.moveTo(x,y);

		content = "<html>";
		content += "<head>";
		content += "<title>Ayuda</title>";
		content += "</head>";
		content += "<body>";
		content += "<img src="+ imagen+" />";
		content += "</body>";
		content += "</html>";
		
		my_window.document.write(content);
		
		my_window.focus();
		setTimeout('my_window.close()',5000);
	}	
	
	
	function MoveNext(field, nextfield, maxlength)
	{	
		if (window.event.keyCode == "9" || window.event.keyCode == "16")
		{
			field.select();
			window.event.keyCode == "16";
		}
		else
		{	
			if (field.value.length==maxlength)
				document.getElementById(nextfield).select();
		}
	}
	
	
	function Habilitar_txt(field, txt)
	{
		if (document.getElementById(field).value==1)
		{
			document.getElementById(txt).disabled=false;
			document.getElementById(txt).value='';
		}
		else
		{
			document.getElementById(txt).disabled=true;
			document.getElementById(txt).value='0';
		}
	}
	
	function mayusculas(field)
	{
		if (window.event.keyCode== "9")
		{
			field.focus();
			field.select();
		}
		else
		if (window.event.keyCode!= "37" && window.event.keyCode!= "38" && window.event.keyCode!= "39" && window.event.keyCode!= "40" && window.event.keyCode!= "46" && window.event.keyCode!= "8" && window.event.keyCode!= "36" && window.event.keyCode!= "9")
		{
		
			var s = field.value
			s = s.toUpperCase();
			field.value = s;
		}
	}
	function ClearHtmlTags()
	{
		for(var i=0;i<document.forms[0].elements.length;i++)
		{
				if (document.forms[0].elements[i].type == "text" || document.forms[0].elements[i].type == "textarea")
				{
					if (document.forms[0].elements[i].value.indexOf("<") >= 0)
					{
						do
						{
							document.forms[0][i].value = document.forms[0].elements[i].value.replace("<","&lt;")
						}
						while (document.forms[0].elements[i].value.indexOf("<") >= 0);
					}                
					if (document.forms[0].elements[i].value.indexOf(">") >= 0)
					{    
						do
						{
							document.forms[0][i].value = document.forms[0].elements[i].value.replace(">","&gt;")
						}
						while (document.forms[0].elements[i].value.indexOf(">") >= 0);
					}
				}
		}
	}