JSFiddle - React, Tailwind, and code Playground

HTML

<input tabindex="3" type="text" name="wr_1" value="a" id="wr_1" required class="frm_input required" size="20" placeholder="회사명" title="회사명"> 
<button onclick="test()">
go
</button>

JavaScript

function test(){
var target = document.getElementById("wr_1").value; // 기본 javascript 
  //var target = $("#wr_1).val() ; // 기본 Jquery 사용시 
  if ( target != "회사명" && target.length < 1) { 
                alert("회사명을 입력하세요."); 
                f.wr_1.focus(); 
                return false; 
  } 
}