如何重复从php文件中获取数据直到达到某个条件？

Question

I have a php file that gets a word from a database randomly and json encodes it. I want to get the word using jquery but also make sure that word isn't in a list already. I'm confused on how I can repeatedly hit the server till my condition is met. Here is what I have:

php:

 <?php
    $sql = "SELECT * FROM words ORDER BY RAND() LIMIT 1";
    $result = $db->query($sql);

    $row = $result->fetch_assoc();
    $word = $row['word'];
    echo json_encode($word);
    ?>

Jquery function:

$(document).ready(function() {
    $("#newRound").on("click",function(){
        $.getJSON("getWord.php",function(data){
            //check here if data is already in wordsSoFar arary and if it is, get another word from getword.php
            document.getElementById("input1").style.visibility = 'visible';
            currentWord = data; //set the current work
            lives = 6; //reset lives
            tracker = 0; 
            incorrectLettersGuessed = "";
            allGuessedLetters = "";
            updateLetters();
            document.getElementById('hangman').innerHTML = '<center><img src="stage1.png"></center>';
            createTable(currentWord);
            output.innerHTML = '<center>'+messages.validLetter + '</center>';
            alert(currentWord);
        });
    });
});

Answer 1

if you want a sql solution:

$sql = "SELECT * FROM words WHERE column_name NOT IN ('yourword1','yourword2','youword3'...) ORDER BY RAND() LIMIT 1";

EDIT: i saw your comment too late (Check it on client side).

here a jquery solution (because youre working with jQuery):

$.each(yourwordsarray, function( index, value ) {
  if(value == word_is_in){
.. do what you want with the word
}
});