The X-axis object

<script>
   bar = new RGraph.Bar({
        id: 'cvs',
        data: [4,8,6,5,6,9,9,4],
        options: {
            xaxis: false,
            yaxis: false,
            textSize: 14,
            marginBottom: 45,
            colors: ['gradient(white:red)'],
            shadow: false,
            backgroundGridVlines: false,
            backgroundGridBorder: false
        }
    }).draw();
    
    new RGraph.Drawing.XAxis({
        id: 'cvs',
        y: bar.canvas.height - bar.marginBottom,
        options: {
            tooltips: ['The X-axis represents each>br /<person teaching at the college.'],
            xaxisLabels: ['Rich','Alex','Johnny','Kev','Pete','Luis','John','Barry'],
            xaxisTickmarksCount: 8,
            colors: ['#666']
        }
    }).draw();
</script>

colors
An array of colors. Even though it's an array only the first color is used.
Default: ['black']

marginLeft
The left margin of the axis. This can be the same or different to the chart.
Default: 35

marginRight
The right margin of the axis. This can be the same or different to the chart.
Default: 35

marginTop
The top margin of the axis.
Default: 35

marginBottom
The bottom margin of the axis.
Default: 35

marginInner
The (inner) horizontal margin of the axis. Useful for matching up labels/points of the Line chart.
Default: 0

function myFormatter(obj, num)
{
    return num + 'F'; // An example of formatting
}

xaxis
Set this to true if you don't want an x-axis.
Default: true

xaxisPosition
This determines where the x-axis is positioned. If you wish to show negative values then you should set this to center or you can now (Jul 2016) use an offset x-axis by leaving this property at the default bottom and using the yaxisScaleMax and yaxisScaleMin properties.
Default: bottom

xaxisLinewidth
The linewidth used for the x-axis and the x-axis tickmarks.
Default: 1

xaxisColor
The color of the x-axis (and its tickmarks.
Default: black

xaxisTickmarks
Whether the x-axis tickmarks are shown.
Default: true

xaxisTickmarksLastLeft
Whether the last tickmark on the left is displayed.
Default: null

xaxisTickmarksLastRight
Whether the last tickmark on the right is displayed.
Default: null

xaxisTickmarksLength
The length of the tickmarks.
Default: 3

xaxisTickmarksCount
The number of tickmarks that are shown on the x-axis.
Default: null

xaxisLabels
An array of the labels to be used on the chart.
Default: An empty array

xaxisLabelsFont
The font used to render the labels.
Default: null

xaxisLabelsSize
The size of the labels.
Default: null

xaxisLabelsColor
The color of the labels.
Default: null

xaxisLabelsBold
Whether the labels are bold or not.
Default: null

xaxisLabelsItalic
Whether the labels are italic or not.
Default: null

xaxisLabelsOffsetx
This allows you finer-grained control in the horizontal direction over the X label positioning if you need it.
Default: 0

xaxisLabelsOffsety
This allows you finer-grained control in the vertical direction over the X label positioning if you need it.
Default: 0

xaxisLabelsHalign
The horizontal alignment of the labels.
Default: center

xaxisLabelsValign
The vertical alignment of the labels.
Default: top

xaxisLabelsAngle
The angle of the x-axis labels. For example, you could set this to 45 to get angled labels.
Default: 0 (Horizontal)

xaxisLabelsPosition
This property controls how the labels are arranged - section for most chart types and edge for Line charts. You probably won't need to change this.
Default: section

xaxisLabelsClass
This property allows you to add your own css class to the x-axis labels which you can then use for styling purposes or to make retrieving the span tags easier (the dom elements). If you inspect the labels in your browser's javascript console (you will first need to enable the textAccessiblePointerevents property) you will be able to see the other css classes that are assigned to the labels.
Default: [none]

xaxisTitle
This allows you to specify a title for the x-axis.
Default: none

xaxisTitleSize
This allows you to specify a size for the x-axis title.
Default: null

xaxisTitleFont
This allows you to specify a font for the x-axis title.
Default: null

xaxisTitleBold
This controls whether the x-axis title is bold or not.
Default: null

xaxisTitleItalic
This controls whether the x-axis title is italic or not.
Default: null

xaxisTitleColor
This controls the color of the x-axis title.
Default: null

xaxisTitleX
By giving this you can specifically set the X position of the x-axis title.
Default: null

xaxisTitleY
By giving this you can specifically set the Y position of the x-axis title.
Default: null

xaxisTitleOffsetx
The X pixel offset that's applied to the title.
Default: 0

xaxisTitleOffsety
The Y pixel offset that's applied to the title.
Default: 0

xaxisTitleHalign
The horizontal alignment of the title.
Default: center

xaxisTitleValign
The vertical alignment of the title.
Default: top

xaxisTitlePos
This is a multiplier (ie a digit usually between 0 and 1) that gets multiplied with the margin to get the Y position of the title.
Default: null

xaxisScale
If true then an X scale is drawn instead of X labels.
Default: false

xaxisScaleUnitsPre
These are units that are prepended to the number.
Default: none

xaxisScaleUnitsPost
These are units that are appended to the number.
Default: none

xaxisScaleDecimals
The number of decimals used for the X scale. If not specified the scaleDecimals property is used.
Default: null

xaxisScalePoint
The character that's used as a decimal point.
Default: .

xaxisScaleThousand
The character that's used as the thousand separator.
Default: ,

xaxisScaleFormatter
This can be a function, which is passed the object and the number and should return a formatted number (formatted as you wish).

function myFormatter(obj, num)
{
    return num + 'F'; // An example of formatting
}

Default: null

xaxisScaleLabelsCount
This is a number representing how many X labels there should be when you're using the X scale.
Default: 10

xaxisScaleMin
The minimum x-axis value you wish to set.
Default: 0

xaxisScaleMax
The maximum x-axis value you wish to set. For example, if you're displaying products sold in a year, you might use 365.
Default: none - must be supplied if you want to show a scale

yaxisPosition
This can facilitate when you have a y-axis in the center (eg the Horizontal Bar chart).
Default: left

<div style="margin-left: 50px; display: inline-block">
    <canvas id="cvs" width="650" height="250"></canvas>
</div>

textColor
The color of the text. If not specified then it's the same as the colors option.
Default: null

textFont
The font used when rendering the text.
Default: Arial

textSize
The size used when rendering text.
Default: 10

textBold
Whether the text is bold or not.
Default: 10

textItalic
Whether the text is italic or not.
Default: 10

textAccessible
A new feature in 2016 that allows you to use dom text in place of canvas text. It makes for much higher quality text that you can also select if desired (for copy/paste operations). It won't fit all situations and you can read more about the DOM text feature here. A good way to control borders/margins/padding etc is not to set them on the canvas but to wrap the canvas in a div and set them on that like this:

<div style="margin-left: 50px; display: inline-block">
    <canvas id="cvs" width="650" height="250"></canvas>
</div>

Default: false

text
This allows you to add custom text to your chart if you want to. There's a dedicated page that describes this option here.
Default: null

tooltipsFormattedListItems: [
    ['Bill','Jerry','Berty'], // First tooltip
    ['Gill','Carrie','Lucy'], // Second tooltip
    ['Pob','Nobby','Hilda']   // Third tooltip
]

.RGraph_tooltip ul#rgraph_formatted_tooltips_list li {
    text-align: left;
    color: yellow;
}

tooltips: {
    borderLeft: 'gray 2px solid',
    borderBottom: 'gray 2px solid'
}

tooltipsCss: {
    fontFamily: 'Verdana',
    fontSize: '20pt'
}

tooltips
This can be an array of tooltips (only the first element is used) that are shown when the axis is clicked on.
Default: null

tooltipsEvent
This is the event that triggers the tooltips. It can be either click or mousemove.
Default: onclick

tooltipsEffect
The effect used for showing tooltips. Can be either fade or none.
Default: fade

tooltipsCssClass
This is the name of the css class the chart uses.
Default: RGraph_tooltip

tooltipsOverride
If you wish to handle showing tooltips yourself, this should be a function object which does just that. There's more information on the tooltips documentation page.
Default: null

tooltipsNohideonclear
Not an option that you'll need particularly often if at all. Setting this to true means that when you call the RGraph.clear api function tooltip DO NOT get hidden.
Default: false

tooltipsFormattedPoint
When using formatted tooltip strings this is used as the point when using the %{value_formatted} option.
Default: .

tooltipsFormattedThousand
When using formatted tooltip strings this is used as the thousand separator when using the %{value_formatted} option.
Default: ,

tooltipsFormattedDecimals
When using formatted tooltip strings this specifies the number of decimals when using the %{value_formatted} option.
Default: 0

tooltipsFormattedUnitsPre
When using formatted tooltip strings these units are prepended to the number when using the %{value_formatted} option.
Default: (an empty string)

tooltipsFormattedUnitsPost
When using formatted tooltip strings these units are appended to the number when using the %{value_formatted} option.
Default: (an empty string)

tooltipsFormattedListType
With this property you can switch between an unordered list (the default) and an ordered list. Possible values are ul and ol.
Default: ul

tooltipsFormattedListItems
This should be a two-dimensional array of the list items that are to be shown for all of the tooltips. An example of this property is:

tooltipsFormattedListItems: [
    ['Bill','Jerry','Berty'], // First tooltip
    ['Gill','Carrie','Lucy'], // Second tooltip
    ['Pob','Nobby','Hilda']   // Third tooltip
]

You can use css to style this list - for example:

.RGraph_tooltip ul#rgraph_formatted_tooltips_list li {
    text-align: left;
    color: yellow;
}

Default: null

tooltipsFormattedTableHeaders
When showing a table in the tooltips this can be an array of headers for the table. These are added to the tooltip using th tags.
Default: null

tooltipsFormattedTableData
This is the data that is added to the table. This is a 3-dimensional array so it's easy to make a mistake. See the example, copy the code from it and then modify it suit. You'll create fewer bugs this way.
Default: null)

tooltipsPointer
By default the tooltips have a small triangular pointer that points to the shape that was clicked on. You can turn this off with this property.
Default: true

tooltipsPointerCss
If you want any css values applied to the tooltips pointer (for example, a css border) then specify an object containing those values to this property. For example:

tooltips: {
    borderLeft: 'gray 2px solid',
    borderBottom: 'gray 2px solid'
}

Default: null

tooltipsPointerOffsetx
This allows you to adjust the vertical position of the tooltips pointer.
Default: 0

tooltipsPointerOffsety
This allows you to adjust the vertical position of the tooltips pointer (for example, if you add a border you may need to move it down slightly).
Default: 0

tooltipsPositionStatic
The new default (as of August 2020) is for tooltips to be positioned statically and not be dependent on the mouse position. If you don't want this for whatever reason, you can disable it with this setting. When you set it to false tooltips are positioned next to the mouse pointer.
Default: true

tooltipsCss
If you want to specify some css that gets applied to all of the tooltips, but don't want to use the RGraph.tooltips.style object (which gets applied to all of the tooltips on the page for every chart) you can use this property to give some per-object css for the tooltips. These are css styles that get applied to all of the tooltips for the specific object only. It should look like this:

tooltipsCss: {
    fontFamily: 'Verdana',
    fontSize: '20pt'
}

Default: null

tooltipsOffsetx
This property allows you to shift the tooltips left or right.
Default: 0

tooltipsOffsety
This property allows you to shift the tooltips up or down.
Default: 0

highlightStyle
By default this is null but you can set it to a function if you wish so that function is called to do the chart highlighting. It's passed the shape object as an argument.
Default: null

linewidth
The linewidth that's used to draw the axis.
Default: 1

<script>
    xaxis.canvas.onclick = function (e)
    {
        RGraph.redraw();
    
        var canvas = e.target,
            obj    = canvas.__object__,
            shape  = obj.getShape(e);

        if (shape) {            
            // Highlight the main body of the x-axis object.
            obj.path(
                'lw 10 b r % % % % s black f rgba(255,0,0,0.25)',
                shape.x, shape.y, shape.width, shape.height
            );
        }
    }
</script>

obj.on('draw', function (obj)
{
    // Put your event code here
});

obj = new RGraph.Drawing.XAxis({
    id: 'cvs',
    options: {
    }
}).on('draw', function (obj)
{
    // Put your draw event code here

}).on('click', function (e, shape)
{
    // Handle the click event

}).draw();