JSFiddle - React, Tailwind, and code Playground
HTML
<input id="x" type="number" value="4212321254+"/>
JavaScript
/* alert(document.getElementById("x").innerHTML.replace(/[^0-9]/g, "")); */
alert(document.getElementById("x").textContent);
<input id="x" type="number" value="4212321254+"/>
/* alert(document.getElementById("x").innerHTML.replace(/[^0-9]/g, "")); */
alert(document.getElementById("x").textContent);