I happened to have a copy of MIL-STD-1472 handy (mine is Rev F dated 23 August 1999). It's more or less the human-machine interface bible for military programs. Below is what it says about flashing rates, for the curious. Mozilla's flash rate of 1 Hz with a duty cycle of 75% tracks nicely with the "caution signals" usage. Note that if people followed the guidelines for not flashing text that must be read and for flashing a small area, it might be useful (though how much of the Web is mission-critical?) As it stands, it's an irritation IMNSHO, though I must admit I haven't seen a page with it in some time.
Best regards, Alan Hohn 5.2.1.1.4.1 Warning signals. Visual warning signals should be presented using flashing red with flash frequency between 3 and 5 Hz with a 50% duty cycle. The flash rate for all such warning signals shall be synchronized. If used in conjunction with caution signals, warning signals should be coded to be easily distinguished from caution signals. 5.2.1.1.4.2 Caution signals. Visual caution signals should be yellow. A minimum of two discriminatory characteristics should be employed to ensure rapid identification and interpretation of caution signals. If used in conjunction with warning signals, caution signals should be not more than half the intensity of the warning signal. If cautions take the form of flashing text, the text should flash at a rate not greater than 2 Hz with ON/OFF interval of about 70% on. 5.2.1.5.5.2 Duty cycle. The percentage of "on" time should be equal to but not less than the percentage of "off" time. A 50% duty cycle is preferred. 5.2.1.5.5.3 Flash rate. No more than two flash rates should be used and they shall differ by not less than 2 Hz. The higher flash rate shall reflect the more critical information and should be not greater than 5 Hz. The slower flash rate shall be not less than 0.8 Hz. If possible, flashing should be synchronized. 5.2.1.5.5.4 Text. Characters that must be read should not flash. Emphasis should be added by an adjacent flashing symbol or flashing background. 5.2.1.5.5.5 Flash suppression. Event acknowledgment or flash suppression control should be provided. 5.2.1.5.5.6 Flashing area. Only a small area of a display should flash at any time. 5.14.3.3.2 Flash. Flash coding shall be employed to call the user's attention to mission critical events only. No more than 2 flash rates shall be used. Where one rate is used, the rate shall be 3 - 5 flashes per second. Where two rates are used, the second rate shall be not greater than 2 per second. _______________________________________________ mozilla-layout mailing list [EMAIL PROTECTED] http://mail.mozilla.org/listinfo/mozilla-layout
