Just override in this way it will work definitely
function tooltipContent(key, y, e, graph) {
return '<h3>' + key + '</h3>' +'<p>' + y + '</p>' ;
}
Or
tooltipContent(function(key, y, e, graph) { return 'Some String' })
Just override in this way it will work definitely
function tooltipContent(key, y, e, graph) {
return '<h3>' + key + '</h3>' +'<p>' + y + '</p>' ;
}
Or
tooltipContent(function(key, y, e, graph) { return 'Some String' })