How to register callbacks to the load and exception events of the JsonStore?

var grid = new Ext.grid.GridPanel({
store: new Ext.data.JsonStore({
[...]
listeners: {
load: this.onLoadSuccess.crateDelegate(this),
exception: this.onLoadException.createDelegate(this)
}
}),

onLoadSuccess: function () {
// success
},

onLoadException: function () {
// error
},

[...]
}