Someone knows how to solve this problem with char.js

with a button I make a graph with the library char.js , but when I want to return to traffic I get an error:

I'm trying to solve with this code but it does not work.

 $('#myChart_2').remove();
 $('#contenedor_grafico_2').append("<canvas id='myChart_2' width='100' height='30'></canvas>");
 var ctx = $("#myChart_2");