When you create a Dygraph object, your code looks something like this:
g = new Dygraph(document.getElementById("div"),
data,
{ options });
This document is about some of the values you can put in the options parameter.
Typically, an option applies to the whole chart: if you set the strokeWidth option, it will apply to all data-series equally:
g = new Dygraph(document.getElementById("div"),
"X,Y1,Y2,Y3\n" +
"1,2,3,4\n" +
...,
{
strokeWidth: 5
});
Some options, however, can be applied on a per-series or a per-axis basis. For instance, to set three different strokeWidths, you could write:
g = new Dygraph(document.getElementById("div"),
"X,Y1,Y2,Y3\n" +
"1,2,3,4\n" +
...,
{
strokeWidth: 5, // default stroke width
'Y1': {
strokeWidth: 3 // Y1 gets a special value.
},
'Y3': {
strokeWidth: 1 // so does Y3.
}
});
The result of these options is that Y1 will have a strokeWidth of 1, Y2 will have a strokeWidth of 5 and Y3 will have a strokeWidth of 1. You can see a demonstration of this here.
Some options make more sense when applied to an entire axis, rather than to individual series. For instance, the axisLabelFormatter option lets you specify a function for format the labels on axis tick marks for display. You might want one function for the x-axis and another one for the y-axis.
Here's how you can do that:
g = new Dygraph(document.getElementById("div"),
"X,Y1,Y2,Y3\n" +
"1,2,3,4\n" +
...,
{
axes: {
x: {
axisLabelFormatter: function(x) {
return 'x' + x;
}
},
y: {
axisLabelFormatter: function(y) {
return 'y' + y;
}
}
}
});
The keys in the 'axes' option are always 'x', 'y' and, if you have a secondary y-axis, 'y2'. If you set the "axisLabelFormatter" option at the top level, it will apply to all axes.
To see this in practice, check out the two-axes test.