Can't execute javascript via URL Bar
https://support.mozilla.com/en-US/questions/871548 I suffer from this, the solution to use a bookmark works however I want to know how and what changes prevent the use of the URL Bar for such things.
Sometimes Firefox will respond to it being pasted in the URL Bar and sometimes it won't. there does not seem to be any logic behind it hence my question.
Edit: and just for the sake of it, not really important but how do you make mailto links always open in a new tab?
Modified by Franpa
Chosen solution
Javascript runs with different levels of acces rights. When you type something in the URLbar, it get no access rights (Null principal - starting in Firefox 6 see question 876916), so you can do almost nothing. A bookmarklet runs with page access rights, so it can do more like alert("hello") etc. Javascript that runs inside an add-on has maximum power and can do everything "chrome privileges".
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Chosen Solution
Javascript runs with different levels of acces rights. When you type something in the URLbar, it get no access rights (Null principal - starting in Firefox 6 see question 876916), so you can do almost nothing. A bookmarklet runs with page access rights, so it can do more like alert("hello") etc. Javascript that runs inside an add-on has maximum power and can do everything "chrome privileges".
You can use the Scratch pad (Firefox > Web Developer > Scratchpad; Shift+F4) to run JavaScript code (Ctrl+R).