SMS Link Builder

You want a Text us button on a landing page and immediately hit the syntax question: is it sms:+15551234567?body= or &body=? Then the message picks up a space, an apostrophe or an accent and the link falls apart halfway through. It works on your Android, you ship it, and someone on an iPhone reports an empty compose screen. This builder writes the form both platforms accept.

Two fields: phone and message. The phone runs through a filter that keeps only digits and the plus sign, so parentheses, dashes and spaces drop out on their own. The message goes through encodeURIComponent, turning Hello there! into Hello%20there%21. Leave the message empty and the ?body= part disappears from the output entirely. Everything is rebuilt as you type, right in the page.

Write the number in international form, with the plus sign and country code, since that travels best across carriers. Test on a real handset, because desktop browsers usually ignore sms: links altogether. And remember the link sends nothing on its own. It opens the messaging app with recipient and text filled in, and the person still has to hit send, on their own plan. Bulk campaigns need a real gateway instead.