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First of all you should name your new script and enter a short description. You can also select whether the script runs when the page is loaded or when the case is saved.
You can read more about On Load scripts here and more about On Save scripts here.
You can also select which case types the script will run be active in.
Add script content
Once you have entered the details of the script, you are free to write the script itself in the "Script Content" box. Users that are familiar with JavaScript will have free reign over their case behavior. If you do not have extensive experience with javascript, you can consult out example scripts here for some basic script types and tweak them for your system
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