This step by step guide will show you how the provide a slider control for a number field in a SharePoint list:
- Download the following code and upload the file in your Style Library or Site Assets Library.
- Open the list where you want to modify the edit form and click on edit item.
- Click on the gear icon in the upper right corner and click on edit page.
- Hover over the right corner of the web part and click on Edit Web Part
- Click OK
Hope it helps!
If you want more information, please review the following http://code.msdn.microsoft.com examples.