background.js

var uselessWords = ["is","of","the","on","off","was","i","","has","have","had","will","a","in","that","it","an","its","and","by","be","."," "]


chrome.runtime.onMessage.addListener(
  
    function(request, sender, sendResponse) {
        console.log(sender.tab ?
                "from a content script:" + sender.tab.url :
                "from the extension");

        var wordArray=request.words.split(/\r\n|\n|\r/);
        var scoresArray=request.score.split(/\r\n|\n|\r/);
        var htmlWords=($("body").text().split(/\s+/));
        var arrToLow = String.prototype.toLowerCase.apply(htmlWords).split(",");
        var diff = $(arrToLow).not(uselessWords).get();
        var value = 0;
        var count=0;
        var happyCount=0,sadCount=0;
        var k=0;

        for (var i = 0; i < wordArray.length; i++) {
          for (var j =0; j < diff.length-1; j++) {
             if (diff[j]==wordArray[i]) {
              
                value+=parseInt(scoresArray[i]);
                count=count+1;
                if (parseInt(scoresArray[i])>7) {
                  happyCount+=1;
                }
                else if (parseInt(scoresArray[i])<3.5) {
                  sadCount+=1;
              }
             }
           }
           k=i; 
        }

        if(k==wordArray.length-1){

          console.log(happyCount+" sad "+sadCount)

          if(happyCount==0&&sadCount==0)
          {
              sendResponse({val:-1});
          }
          else
          {
            sendResponse({val: value/count});
          }

         
          
        }
        
});