How to clear a text field in an on edit on load script?

How to clear a text field in an on edit on load script?

The clear command doesnt seem to be used for common text fields.  I need to clear a text field on edit on load with a script.  How can I do this?  I cant just add a " " (blank space) because it needs to be completed and compared to another field for accuracy.  Please advise.  Thanks.