HTML form look:

<form action=search id=searchForm onsubmit=return validateSearch()>

    <input type=text name=byTitle pattern=[a-zA-Z0-9]+ placeholder=Enter a word from title>

    <input type=text name=byAuthor pattern=[a-zA-Z]+s[a-zA-Z]+ placeholder=First-name Last-name> <!--  pattern=w+ w+ -->

    <input id=startDate name=startDate type=date>

    <input id=endDate name=endDate type=date>

    <input type=submit name=submit value=Submit>

</form>

Javscript validating function:

function validateSearch() {



    var byTitle   = document.getElementById('searchForm').byTitle.value;

    // alert(byTitle);

    var byAuthor  = document.getElementById('searchForm').byAuthor.value;

    // alert(byAuthor);

    var startDate = document.getElementById('searchForm').startDate.value;

    //alert(startDate);

    var endDate   = document.getElementById('searchForm').endDate.value;

    //alert(endDate);       



    if(byTitle == byAuthor == startDate == endDate == ){

        alert(Enter at least one search parameter!);

        return false;

    }

}

Now, if I leave all form fields empty/unfilled and press submit, alert(Enter at least one search parameter!); message should pop-up, but it doesn't. Wanted to see what are the values of each field I have inserted alert after each field reading, and they are all same, empty string/blank. So, why is then that if condition not seeing them as same, empty fields?