how to change default keyboard language in name prompt?

Question

i use this script in my website:

let displayName = "";
const namePrompt = prompt("אנא הכנס שם ולחץ על אישור‫,‬ לכניסה ללא שם לחץ על ביטול‫.‬");

if (namePrompt !== null) {
  displayName = "⠀-⠀" + namePrompt;
}

document.getElementById("framed").src = "http://www.myurl.com" + displayName;

then a popup appears that asks the user to enter his name and when the user start to type, the default language is english.

how can i set the default language to hebrew for example? so when this name prompt will appear, the user will not need to switch from english to hebrew before he writes his name.. it will be hebrew by default and the user will be able to switch into english if needed.

thanks.