function FormataValor(campo, tammax, teclapres) 
{
    var tecla = teclapres.keyCode;
    vr = campo.value;
    vr = vr.replace( "/", "" );
    vr = vr.replace( "/", "" );
    vr = vr.replace( ",", "" );
    vr = vr.replace( ".", "" );
    vr = vr.replace( ".", "" );
    vr = vr.replace( ".", "" );
    vr = vr.replace( ".", "" );
    tam = vr.length;

    if (tam < tammax && tecla != 8)
		tam = vr.length + 1;
    
    if ( tecla >= 48 && tecla <= 57 || tecla >= 96 && tecla <= 105 )
	{
        if ( tam <= 3 )
             campo.value = vr;
         
		 if ( (tam > 3) && (tam <= 6) )
             campo.value = vr.substr( 0, tam - 3 ) + ',' + vr.substr( tam - 3, tam ); 
         
		 if ( (tam >= 7) && (tam <= 9) )
             campo.value = vr.substr( 0, tam - 6 ) + '.' + vr.substr( tam - 6, 3 ) + ',' + vr.substr( tam - 3, tam );
			 
		if ( (tam >= 10) && (tam <= 11) )
             campo.value = vr.substr( 0, tam - 9 ) + '.' + vr.substr( tam - 9, 3 ) + '.' + vr.substr( tam - 6, 3 ) + ',' + vr.substr( tam - 3, tam );	 
    }            
}