Underline API in JavaScript DocumentEditor API control

Enum underline for character format

• None
• Single
• Words
• Double
• Dotted
• Thick
• Dash
• DashLong
• DotDash
• DotDotDash
• Wavy
• DottedHeavy
• DashHeavy
• DashLongHeavy
• DotDashHeavy
• DotDotDashHeavy
• WavyHeavy
• WavyDouble