Joomla range Form Field Type
The range form field type provides a horizontal slider for numeric input. There is no indication of the actual value being chosen, just the position of the slider's thumb. The range field type extends the number field type.
XML Field Definition
<field name="myrange"
type="range"
label="Range from -0.5 to 0.5 step 0.1"
min="-0.5"
max="0.5"
step="0.1" />
This will create a slider with possibility to choose values between 0 and 0.5 and change current value by 0.1 as the slider is moved left or right.
Additional Parameters
min: This value is the lowest that can be chosen.
max: This value is the highest that can be chosen.
step: If user clicks up or down arrow current, the value will change by this attribute. This attribute value will be added or subtracted to current field value. It defaults to 1.