doctype html
script src=src="https://code.jquery.com/jquery-3.1.1.min.js"
p 
  span zip:
  input value="386-1298"
  button go
#result
javascript:
  function go() {
    var zip=$('input').val()
    console.log(`zip=${zip}`)
    $.get(`http://zipcloud.ibsnet.co.jp/api/search?zipcode=${zip}`,(data)=>{
      $('#result').textContent=data
    })
  }
  $('button').click(go)