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POChanging website content dynamically depending on MySQL database value
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  1. POChanging website content dynamically depending on MySQL database value
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    copied!<p>I want to change my website dynamically based on a value. I retrive data from my MySQL database and want the change to be as close to real-time as possible. I have some code that does what I want to some extent, but the updating of the values seem to fail, at first it works and then after a few calls it seems to just switch at random between the two values. </p> <p>I have three php pages, one that retrives a value from the database (database.php) and two that generate a response based on the database value(response1.php and response2.php). I do not think that these pages are part of the problem, since I have checked that they return values and they return what I want. The second part of the project (and where it probably fails) is my main html page (below). I am unsure if I have chosen the best technique to solve my problem or if there is a better way to do it.</p> <pre><code>&lt;html&gt; &lt;head&gt; &lt;script type="text/javascript"&gt; var databaseanswer, xmlhttp; function databasecheck() { xmlhttp = new XMLHttpRequest(); xmlhttp.open("GET", "database.php", true); xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState == 4 &amp;&amp; xmlhttp.status == 200) { databaseanswer = xmlhttp.responseText; document.getElementById("database").innerHTML = xmlhttp.responseText; } }; xmlhttp.send(); } function response() { if (databaseanswer == "No Tag") { xmlhttp = new XMLHttpRequest(); xmlhttp.open("GET", "response1.php", true); xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState == 4 &amp;&amp; xmlhttp.status == 200) { document.getElementById("response").innerHTML = xmlhttp.responseText; } }; xmlhttp.send(); } else { xmlhttp = new XMLHttpRequest(); xmlhttp.open("GET", "response2.php", true); xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState == 4 &amp;&amp; xmlhttp.status == 200) { document.getElementById("response").innerHTML = xmlhttp.responseText; } }; xmlhttp.send(); } } setInterval(databasecheck, 1800); setInterval(response, 2000); &lt;/script&gt; &lt;/head&gt; &lt;body&gt; &lt;p&gt; this is a test site &lt;/p&gt; &lt;p&gt; response from server: &lt;/p&gt; &lt;div id="response"&gt; &lt;/div&gt; &lt;p&gt; answer from database: &lt;/p&gt; &lt;div id="database"&gt; &lt;/div&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <p><strong>Okay, so this is my edited code:</strong></p> <pre><code>&lt;html&gt; &lt;head&gt; &lt;script&gt; function database(){ var xmlhttp = new XMLHttpRequest(); xmlhttp.open("GET","responsedatabase.php",false); xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 &amp;&amp; xmlhttp.status==200) { document.getElementById("database").innerHTML=xmlhttp.responseText; } } xmlhttp.send(); } setInterval(database,1000); &lt;/script&gt; &lt;/head&gt; &lt;body&gt; &lt;p&gt;answer from database: &lt;/p&gt;&lt;div id="database"&gt;&lt;/div&gt; &lt;/body&gt; &lt;/html&gt; </code></pre>
 

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