JSFiddle - React, Tailwind, and code Playground

by funato

JavaScript

function numberFormat(source){
	var s=new String(source);
	var ret='';
	
	for (var i=s.length-3; i>0; i-=3){
		ret=','+s.substr(i,3)+ret;
	}
	ret=s.substr(0,i+3)+ret;
	
	return ret;
}
document.write('合計金額は、'+numberFormat(2890*5)+'円です<br>');