Change the value of a slider control:
document.getElementById("myRange").value = "75";
The value property sets or returns the value of the value attribute of a slider control.
The value attribute specifies the default value OR the value a user types in (or a value set by a script).
The value property is supported in all major browsers.
Note: The <input type="range"> element is not supported in Internet Explorer 9 and earlier versions.
Return the value property:
rangeObject.value
Set the value property:
rangeObject.value=number