This below sample script shows how nlapiRemoveSelectOption works in Client Scripts Page Init function.
1. Create a User Event script under Customization > Scripting > Scripts > New > User Event to add a field SELECT before load. Deploy the script to customer record.
//Add a tab to the Intern form.
var firstTab = form.addTab('custpage_academichistorytab', 'Academic History');
var select_fld = form.addField('custpage_selectfield','multiselect', 'Select');
2. Create a Client script under Customization > Scripting > Scripts > New. Use the PageInit function to remove one of the options in the Select field. Deploy the Client script to customer record.
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