function crearAjax(){
   var xmlhttp=false; 
    try 
    { 
        xmlhttp=new ActiveXObject("Msxml2.XMLHTTP"); 
    }
    catch(e)
    { 
        try
        { 
            xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); 
        } 
        catch(E) { xmlhttp=false; }
    }
    if (!xmlhttp && typeof XMLHttpRequest!='undefined') { xmlhttp=new XMLHttpRequest(); }  
      return xmlhttp;
}

function soloNumeros(evt){
//asignamos el valor de la tecla a keynum
    if(window.event){// IE
    keynum = evt.keyCode;
    }
    else{
    keynum = evt.which;
    }
//comprobamos si se encuentra en el rango
    if(keynum>47 && keynum<58 || keynum==8 || keynum==0 || keynum==13){
        return true;
    }else{
        return false;
    }
}
    
    function dar_tecla(evt){
      if(window.event){// IE
        keynum = evt.keyCode;
    }
    else{
        keynum = evt.which;
    }
    return keynum;  
    }

function fmtMoney( n, c, d, t ) {
    var m = ( c = Math.abs( c ) + 1 ? c : 2, d = d || ".", t = t || ",", /(\d+)(?:(\.\d+)|)/.exec( n + "" ) ), x = (m[1].length > 3)?m[1].length % 3:0;
    m[2] = (parseFloat(m[2]) > 0)?m[2]:0.00;
    return ( x ? m[1].substr( 0, x ) + t : "" ) + m[1].substr( x ).replace( /(\d{3})(?=\d)/g, "$1" + t ) + ( c ? d + ( +m[2] ).toFixed( c ).substr( 2 ) : "" );
}
       

function M2_WindowClose(nombrexp,precioxp) { 
  window.opener.document.xform.nombrearticulo.value =  nombrexp;
  window.opener.document.xform.preciox.value = precioxp;
  window.close();
  return false;
}

function isset(variable_name) {
    try {
         if (typeof(eval(variable_name)) != 'undefined')
         if (eval(variable_name) != null)
         return true;
     } catch(e) { }
    return false;
   }

  function IsNumeric(sText)
{
   var ValidChars = "0123456789.";
   var IsNumber=true;
   var Char;
   var countpoints = 0;
   for (i = 0; i < sText.length && IsNumber == true; i++) 
      { 
      Char = sText.charAt(i); 
      if (Char=="."){
          countpoints ++;
      }
      if (ValidChars.indexOf(Char) == -1) 
         {
         IsNumber = false;
         }
      }
      if (countpoints <= 1){
        return IsNumber;
      }
      else
      return false;
   }

function Trim(str)
{
  return str.replace(/^\s+|\s+$/g, '');
}