The following table provides information about JavaTM applet and JavaScriptTM behavior allowed at each security level in &browser.name.prefix;TM &browser.name.suffix;.
The Unprotected security level is only available on the Special Cases Security Preferences panel. The Blocked security level is applied on the Applets and JavaScript panel when you unset Enable Applets, Enable JavaScript, or both options.
The information in this table describes common applet or JavaScript behavior, relevant to most users. If you are a Java applet or JavaScript developer interested in details about additional technical restrictions at the various security levels (for example, accessing properties and manipulating threads), see the security documentation shipped with the &browser.name; Administrator documents.
Note that in addition to the tangible protections described below, the Java language and &browser.name; work together to enforce other constraints on JavaScript and Java applets to make them run in a safe fashion. For example, applets are not permitted to send messages to windows that cause them to be closed (except windows the applet has created on its own).
Security Restriction Level | ||||
Blocked | Restricted | Ask First | Unprotected | |
Read Files | No | No1 | Warn1 | Yes |
Write Files | No | No | Warn | Yes |
Delete Files | No | No | Warn | Yes |
Exit &browser.name; | No | No | No | No |
Start Local Applications | No | No | Warn | Warn |
Accept Network Connection | No | Limited2 | Warn7 | Yes |
Connect to Another Computer | No | Limited3 | Warn4 | Yes |
Create Windows | No | Yes5 | Yes5 | Yes |
Access System Clipboard | No | No | No | Yes |
Access Print Queue | No | No | No | Yes |
Permissions listed as "Warn" have the following behavior:
Each time JavaScript or a Java applet attempts one of the listed actions, (for example, read a file), &browser.name; checks its list of previously granted permissions. If the specific permission has been previously granted, it is allowed. Otherwise, you are queried through a dialog box to choose from either allowing this specific action (read the specified file), allowing all similar actions (read any file), or blocking the action (deny reading this file this time).Footnotes:
1: JavaScript and applets with Ask First or Restricted security that are loaded using the file protocol have read access (without warning) to files in the directory from which they were loaded.
2: JavaScript and applets with Restricted security may accept connections from their originating site, but no others.
3: Javascript and applets with Restricted security may connect to their originating site, but no others.
4: You are warned and can deny permission when an applet attempts any network access except when connecting to the applet's original site.
5: Windows created by JavaScript or applets with Restricted or Ask First security will show a warning banner at the top of the window.
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