ActionScript for Flash MX: The Definitive Guide, Second Edition

theFormat.underline

Description

The Boolean underline property specifies whether characters are displayed with a line beneath them (true) or without any underline (false).

To underline an entire text field, invoke TextField.setTextFormat( ) without specifying any index arguments:

this.createTextField("theField_txt", 1, 0, 0, 200, 20); theField_txt.border = true; theField_txt.text = "Please enter your name." // Create a TextFormat object format = new TextFormat(); format.underline = true; // Underline the whole field theField_txt.setTextFormat(format);

To underline a single character, apply the format with a single index argument:

theField_txt.setTextFormat(0, format); // Underline the first character ("P")

To underline a range of characters, apply the format with start and end index arguments:

theField_txt.setTextFormat(0, 6, format); // Underline the characters at indexes // 0, 1, 2, 3, 4, and 5 ("Please")

The default underline value (as contained in the TextFormat object returned by TextField.getTextFormat( )) for an existing text field is false; however, for a completely new TextFormat object, it is null, indicating that underline will not be set when the format is applied to a text field:

trace(anyUnformattedField_txt.getTextFormat().underline); // Displays: false var format = new TextFormat(); trace(format.underline); // Displays: "null"

Unlike most web browsers, Flash does not automatically underline hypertext links, so the underline property must be used to indicate links manually, as shown under TextFormat.url.

See Also

TextField.htmlText, TextFormat.url