title: how to concatenate string and variable in Vue js
body: <p>How to concatenate string with two adding variable use Vuejs.  i have used below code but string i am not able to concatenate to variables. please check and solve my issue.</p>
  
  <pre><code>&lt;div id = "vue_det"&gt;
      &lt;h1&gt;Firstname : {{firstname}}&lt;/h1&gt;
      &lt;h1&gt;Lastname : {{lastname}}&lt;/h1&gt;
      &lt;h1&gt;{{test()}}&lt;/h1&gt;
      &lt;/div&gt;
      &lt;script type = "text/javascript" src = "js/vue_instance.js"&gt;&lt;/script&gt;
      &lt;script&gt;
  
       var  vm = new Vue({
     el: '#vue_det',
     data: {
        firstname : 10,
        lastname  : 20,
  
     },
     methods: {
        test : function() {
  
           return "result"+ this.firstname+this.lastname;
        }
     }
  })
       &lt;/script&gt;
     &lt;/body&gt;
  </code></pre>