MAILTO max-length of each internet browsers?

Question

Update: Two years before this question, a similar question was asked: Effective maximum mailto: body lengths as pointed out by Peter O. Luckily answers

Answer 1

Firefox does not impose any limits on the length of URLs other than the system's available memory, so you'll have to look into operating system limits for the maximum length of the parameters when invoking a process.

Additionally, you can set a Web app as your mailto URI scheme handler, and in that case the limit depends on the server accepting the request. Firefox comes with a few options like Gmail and Yahoo! Mail, and you can register your own handler with navigator.registerProtocolHandler. If you're curious, open about:config and filter on "gecko.handlerService.schemes" to see the Web app handlers you have configured in your browser.

I can't say for other browsers, but once you start to depend on so many different variables (browser, available memory, OS, server), it's probably best to try a different strategy.