[英]How to use AJAX to perform a MYSQLI query (prepared statement)
所以我在PHP(部分代碼)中有這個(准備好的語句)mysqli查詢:
#New DB connection
@ $mysqli = new mysqli ('localhost', 'user', 'password', 'database');
#Check DB connection, print error upon failure
if (mysqli_connect_errno()) {
printf("<p>Connect failed.</p> <p>Error: \"%s\"</p>\n", mysqli_connect_error());
exit();
} #if
#Check if userName already exists
$query = "SELECT * FROM users WHERE userName = ?";
$stmt = $mysqli->prepare($query);
$stmt->bind_param("s", $registerUserName);
$stmt->execute();
$stmt->store_result();
$num_results = $stmt->num_rows;
if ($num_results) {
echo "<p>This user already exists. Please click your back button.</p>";
exit;
}; #if
我想在onblur事件上通過Javascript / AJAX執行此操作:
function checkForUser(str) {
var xmlhttp;
if (str=="") {
return;
}
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 (xmlhttp.readyState==4 && xmlhttp.status==200) {
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open(???,true); // not sure what goes here or if I should even use this method
xmlhttp.send();
}
那有可能嗎? 如何? 我找到了一些教程,但它們涉及使用jquery。 我可以不用jquery嗎?
我對您的代碼做了一些更改。 希望對您有所幫助:
#New DB connection
@ $mysqli = new mysqli ('localhost', '…', '…', '…');
#Check DB connection, print error upon failure
if (mysqli_connect_errno()) {
printf("<p>Connect failed.</p> <p>Error: \"%s\"</p>\n", mysqli_connect_error());
exit();
} #if
#Check if userName already exists
$query = "SELECT * FROM wp_users WHERE user_login = ?";
$stmt = $mysqli->prepare($query);
$stmt->bind_param("s", $_GET[registerUserName]);
$stmt->execute();
$stmt->store_result();
$num_results = $stmt->num_rows;
if ($num_results) {
echo "<p>This user already exists. Please click your back button.</p>";
exit;
}; #if
現在,我們可以使用“ /ttt.php?registerUserName=user1”之類的URL來調用它,並執行以下功能:
function checkForUser(uname)
{
var req;
req = null;
if (window.XMLHttpRequest) {
try {
req = new XMLHttpRequest();
} catch (e){}
} else if (window.ActiveXObject) {
try {
req = new ActiveXObject('Msxml2.XMLHTTP');
} catch (e){
try {
req = new ActiveXObject('Microsoft.XMLHTTP');
} catch (e){}
}
}
if (req) {
req.open("GET", "/ttt.php?registerUserName="+encodeURIComponent(uname), false);
//req.onreadystatechange = processReqChange;
req.send(null);
if(req.status == 200) {
return req.responseText;
}
}
return false;
}
在里面
req.open("GET", "/ttt.php?registerUserName="+encodeURIComponent(uname), false);
false表示異步請求和req.send將等待php腳本的響應。
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