Javascript - checking if multiple fields are empty not working

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?