Question

我的想法是，我有这个选择框，当我输入输入文本时，它会使用给定的通配符搜索数据库中的给定公司。

HTML

<span id='errorCompany'></span>
<input type='text' name='search_query_bedrijf' id='search_query_bedrijf' onkeypress='checkForm(\"query_bedrijf\")' placeholder='Search companies'>
<select id='bedrijf' name='bedrijf'>
    PHP code is inside here to get all the data from the database
</select>

的Javascript

function checkForm(type){
    var xmlhttp=new XMLHttpRequest();
    xmlhttp.onreadystatechange=function(){
        if (xmlhttp.readyState==4 && xmlhttp.status==200){
            document.getElementById("bedrijf").innerHTML = xmlhttp.responseText;
        }
    }
    var wildcard = document.getElementById("search_query_bedrijf").value;
    xmlhttp.open("GET","getBedrijven.php?wildcard=" + wildcard,true);
    xmlhttp.send();

    if(document.getElementById("bedrijf").options[0].value == "NoData"){
        document.getElementById("errorCompany").innerHTML = "Not a valid company.";
    }else{
        document.getElementById("errorCompany").innerHTML = "";
    }
}

AJAX

<?php
include("include/connect.php");
$wildcard = $_GET["wildcard"];

if($wildcard == ""){
$sqlSelectWildcardLeverancier = "SELECT * FROM companies";
}else{
$sqlSelectWildcardLeverancier = "SELECT * FROM companies WHERE company LIKE      '%".$wildcard."%'";
}

if(!$res = $mysqli->query($sqlSelectWildcardLeverancier)){
    trigger_error('Fout bij query: '.$mysqli->error);
}else{
    while($row = $res->fetch_assoc()){
        $companyID = $row["companyID"];
        echo "<option value='$companyID'>".$row['company']."</option>";
    }
}
$number_bedrijven = $res->num_rows;
if($number_bedrijven == 0){
    echo "<option value='NoData' selected>No data found for this query</option>";
}
?>

现在这一切都像我应该的那样（它从通配符中获取数据等）当我输入像WallmartQ＆＃39;这样的内容时，它会给我“此查询没有找到数据＆＃34;”但我必须输入另一封信＆＃39; WallmartQE＆＃39;所以它给了我跨度的错误信息下面是一个gif来更好地解释它：http://i.imgur.com/0W0hWUB.gif

Answer 1

只需将options[0].value == "NoData"支票放入异步回调中 - 否则会在响应到达之前执行，并且会在＆＃34; old＆＃34;数据。有关详细信息，请参阅How do I return the response from an asynchronous call?。

function checkForm(type) {
    var xmlhttp=new XMLHttpRequest();
    xmlhttp.onreadystatechange=function() {
        if (xmlhttp.readyState==4 && xmlhttp.status==200) {
            document.getElementById("bedrijf").innerHTML = xmlhttp.responseText;

            if (document.getElementById("bedrijf").options[0].value == "NoData") {
                document.getElementById("errorCompany").innerHTML = "Not a valid company.";
            } else {
                document.getElementById("errorCompany").innerHTML = "";
            }
        }
    }
    var wildcard = document.getElementById("search_query_bedrijf").value;
    xmlhttp.open("GET", "getBedrijven.php?wildcard=" + wildcard, true);
    xmlhttp.send();   
}

从ajax生成的选项中获取options.value

1 个答案: