Application.scala

package controllers

import play._
import play.mvc._
import play.libs._

object Application extends Controller {

    def index = Template
    
    def check(text: String) = {
        val xml = WS.url("https://www.google.com/tbproxy/spell?lang=en&hl=en").body(

            <spellrequest textalreadyclipped="0" ignoredups="0" ignoredigits="1" ignoreallcaps="1">
                <text>{text}</text>
            </spellrequest>

        ).post().getXml()
        
        val mistakes = xml \\ "c" map { elem =>
            (elem \ "@o", elem \ "@l", elem.text)
        }
        
        Template(mistakes)
    }

}

check.html

#{extends 'main.html' /}
#{set title:'Result' /}

<p id="result">
    ${text}
</p>

<script type="text/javascript" charset="utf-8">
    var text = $('#result').text().trim(), mistakes = ${mistakes.json()}.reverse, html = '', o = 0, token
    while(token = mistakes.pop()) {
        html += text.substring(o, token._1)
        o = token._1 + token._2
        html += '<em>' + text.substring(token._1, o) + '</em>'
    }
    html += text.substring(o, text.length)
    $('#result').html(html)
</script>

<hr>

<a href="@{index()}">Back</a>

<style type="text/css" media="screen">
    em {
        color: red;
    }
</style>

index.html

#{extends 'main.html' /}
#{set title:'Home' /}

#{form @check()}
    <textarea name="text"></textarea>
    <br>
    <input type="submit" value="Check!">
#{/form}