Website coding surely is awesome and I recently rialized that JavaScript and Ajax are really essential elements in order to build a outstanting website. I've done the research on internet, but the results weren't that useful. Every code included Jquery, which I don't comprehend. Also JSON is slightly unclear regarding the objects, etc.
W3schools published a few examples on how to generate an Ajax code that reacts with a PHP file. This data is retrieved through 'resonseText'. However this element only retrieves one unselected PHP string.
Is there a method to select specific variables or values from the PHP file and accordingly send it back to the Javascript (Ajax) file, so I can subsequently utilize them for further Javascript coding.
Thank you in advance. (It would greatly help, since Ajax is such a complex form of JavaScript.)
My Ajax code, to send data to the PHP file
if (window.XMLHttpRequest) {
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest() ;
} else {
// code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP") ;
}
xmlhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
var XMLResponse = this.responseText ;
document.getElementById("nameInputNote").innerHTML = "Status: " + XMLResponse ;
}
} ;
xmlhttp.open("GET","ajaxIndex.php?rq1="+valueNameInput,true) ;
xmlhttp.send() ;
The PHP code:
<?php
$rq1 = $_GET['rq1'] ;
if (empty($rq1) ) {
} else {
$sql1 = "SELECT userName FROM users WHERE userName = '{$rq1}' " ;
if ($result1 = mysqli_query($connection, $sql1) ) {
$resultsSql1 = mysqli_num_rows($result1) ;
if ($resultsSql1 == 0) {
echo "vacant" ; //select this value with JS
$permission = "true" ; //and select this value separately with JS
} else {
echo "occupied" ; // or in this senario: select this value
$permission = "false" ; // and this value
// In this case the $permission variable is needed to determine whether a form should be submitted or not.
}
}
}
