What could i do using javascript &/or HTML to create something that compares words entered in text fields, and returns the number of similar words there are?

This might work. I haven't tested it.: First, create the two text areas: <textarea id="a"></textarea> <textarea id="b"></textarea> Now make a javascript function: function compareTextareas(a, b){    var aV = document.getElementById(a).value.split(" ");    var bV = document.getElementById(b).value.split(" ");    var results = {};    for(var a in aV){        for(var b in bV){           if(aV[a] == bV[b]){              results[aV[a]] = aV[a];           }        }    }    var words = "";    for(var word in results){        words += results[word] + " ";    }    alert(words); } Then simply call that function when you want to compare them.