JavaScript Examples Bible - UserWorks Technologies

Chapter 12 ✦ Navigator and Other Environment Objects (Chapter 28)
Example
Use The Evaluator (Chapter 13 in the JavaScript Bible) with your IE4+ browser to
compare the values of the three language-related properties running on your computer.
Enter each of the following statements into the top text box:
navigator.browserLanguage
navigator.systemLanguage
navigator.userLanguage
Don’t be surprised if all three properties return the same value.
Methods
preference(name [, val])
NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5
Compatibility ✓ ✓
Example
The page in Listing 28-2 displays checkboxes for several preference settings, plus
one text box to show a preference setting value for the size of the browser’s disk
cache. To run this script without signing the scripts, turn on codebase principals as
directed in Chapter 46 of the JavaScript Bible. (The listing file on the CD-ROM does
not employ signed scripts.)
One function reads all the preferences and sets the form control values accordingly.
Another function sets a preference when you click its checkbox. Because of
the interaction among three of the cookie settings, it is easier to have the script
rerun the showPreferences() function after each setting rather than you trying to
manually control the properties of the three checkboxes. Rerunning that function
also helps verify that you set the preference.
Listing 28-2: Reading and Writing Browser Preferences
Reading/Writing Browser Preferences
function setPreference(pref, value) {
netscape.security.PrivilegeManager.enablePrivilege(
“UniversalPreferencesWrite”)
navigator.preference(pref, value)
netscape.security.PrivilegeManager.revertPrivilege(
“UniversalPreferencesWrite”)
showPreferences()
}
Continued
405
navigator.preference()