Many Firefox users do not know that they can change the default email client in the web browser easily.
What even fewer know is that it is even possible to not only select desktop email clients but also web based email providers such as Yahoo Mail or Gmail as the default provider for all mailto links.
The mailto links in the format mailto:email@example.com are launched with the default application that has been set in the Firefox web browser.
This application may also be used when scripts or other means are used on websites that provide you with options to send emails.
To change that one needs to open the options of the web browser. Firefox users need to tap on the Alt-key on the keyboard and select Tools > Options from the menu bar that opens up after they do.
This opens the Firefox preferences. There you need to switch to the applications tab. Firefox lists all known file types link types on the page.
You can either scroll down until you find mailto listed there or enter it in the search form at the top.
The right side of the mailto content type reveals the program or service that is currently used by Firefox when these links are clicked on.
A click on the row displays a menu icon that lists other options that you can select for the content type instead.
Next to the default option, a client like Thunderbird or Outlook for example, you find Gmail and Yahoo Mail listed there, an option to set the content type to always ask, and one to pick a local client from the system.If you select the last option a file browser opens up that you use to select an executable file on the system which can be useful if the email client was not detected automatically. This can be the case if you are using a portable program for example.The new action that you have selected for the content type becomes active immediately thereafter. It is highly suggested to give it a try to make sure it is working, especially if you have handpicked a local application for the job which Firefox did not list by default.