function similar_text(str1, str2) {
    var len1 = str1.length;
    var len2 = str2.length;

    var max = Math.max(len1, len2);
	var i, j;

    var similarity = i = j = 0;

    while ((i < len1) && (typeof str2[j] != 'undefined')){
        if (str1[i] == str2[j]) {
            similarity++;
            i++;
            j++;
        } else if (len1 < len2) {
            len1++;
            j++;
        } else if (len1 > len2) {
            i++;
            len1--;
        } else {
            i++;
            j++;
        }
    }
    return Math.round(similarity / max * 100);
}