Many people might want to disable JavaScript in certain pages due to security concerns and some due to the fact that disabling JavaScript reduces the page load time .But certain pages might work only using JavaScript. For example, signing in to various website might require JavaScript. So it might be recommended to have a JavaScript toggle button so that it is easy to disable and enable JavaScript without much hassle.
For Opera this is very simple.
Just follow the following instructions to add JavaScript check box in the view bar or on to any bar.
First open Opera.
Go to tools > appearance.
Go to the buttons tab and select the preferences buttons.
You will be able to see a lot of check boxes like small screen, work offline, and enable JavaScript etc.
Just click on the enable JavaScript check box and drag it to any of the bar, I would recommend the view bar. But you can also put it on the address bar as long as there is enough space. Now just leave the mouse button and you will find that you will have an enable JavaScript check box in that place .By default it will be checked.
Here after when you are going to open websites in which you do not want to load JavaScript then you can uncheck this button before loading the page.
Note: Many pages in the web work properly only when JavaScript is enabled. So disable it only when you do not really need to allow JavaScript.