JavaScript：从 PHP 脚本中提取信息

Question

我遇到的问题是我不确定要开始从我在前面的函数中解析的 PHP 脚本中提取的代码是否正确。首先是代码

function getExibitions()
{
myExhibitionsView = document.getElementById('exhibitioncontent');
option = document.createElement('ul');

 for (var i = 0; i < json.length; i++) {
      option.id = 'exhibitionsAll';
       listCheck = document.createElement('src');
       listCheck.id = "<img src = " + "./images/" + json.exhibits[i].exhibit_image;
      myExhibitionsView.appendChild(option);
      option.appendChild(listCheck);   
       //= json.states[i].image;  
      }

}

我认为在json.something.length 之后必须有一些东西作为遍历数据的方法。

这是 PHP 脚本：

<?php
    $exhibitionsarray = array(
            array("exhibition_id" => "1", "exhibition_title" => "New York, New York", "exhibition_subject" => "New York", "ticket_price" => "10",
                "exhibits" => array(
                    array("exhibit_id" => "3", "exhibit_title" => "Brooklyn Bridge from City Hall Park", "exhibit_description" => "New York, June 2005", "exhibit_image" => "brooklynbridge.jpg", "photographer" => "MLG"),
                    array("exhibit_id" => "6", "exhibit_title" => "Central Park, New York", "exhibit_description" => "New York, June 2005", "exhibit_image" => "centralpark.jpg", "photographer" => "MLG"),
                    array("exhibit_id" => "7", "exhibit_title" => "Chrysler Building at night, New York", "exhibit_description" => "New York, July 2001", "exhibit_image" => "chrysler_building.jpg", "photographer" => "MLG")
                ),
                "locations" => array(
                    array("location_id" => "1", "location_name" => "Kelvingrove Art Gallery and Museum", "location_postcode" => "G3 8AG"),
                    array("location_id" => "3", "location_name" => "Walker Art Gallery", "location_postcode" => "L3 8EL"),
                    array("location_id" => "5", "location_name" => "Tate Modern", "location_postcode" => "SE1 9TG")
                )
            ),
            array("exhibition_id" => "2", "exhibition_title" => "Spanish Cities", "exhibition_subject" => "Spain", "ticket_price" => "15",
                "exhibits" => array(
                    array("exhibit_id" => "9", "exhibit_title" => "Eiffel Bridge, Girona", "exhibit_description" => "Girona, March 2008", "exhibit_image" => "eiffel_bridge.jpg", "photographer" => "LPK"),
                    array("exhibit_id" => "13", "exhibit_title" => "Plaza Mayor, Madrid", "exhibit_description" => "Madrid, June 2010", "exhibit_image" => "plazamayor.jpg", "photographer" => "MLG"),
                    array("exhibit_id" => "14", "exhibit_title" => "Puppy (Day)", "exhibit_description" => "Bilbao, September 2006 - Puppy in daylight", "exhibit_image" => "puppy_day.jpg", "photographer" => "LPK"),
                    array("exhibit_id" => "15", "exhibit_title" => "Puppy (Night)", "exhibit_description" => "Bilbao, March 2011 - Puppy at night", "exhibit_image" => "puppy_night.jpg", "photographer" => "LPK")                                                                      
                ),
                "locations" => array(
                    array("location_id" => "2", "location_name" => "Scottish National Gallery", "location_postcode" => "EH2 2EL")
                )                                               
            ),
            array("exhibition_id" => "3", "exhibition_title" => "A Glasgow Viewpoint", "exhibition_subject" => "Glasgow", "ticket_price" => "5",
                "exhibits" => array(
                    array("exhibit_id" => "2", "exhibit_title" => "Bothwell Castle", "exhibit_description" => "Bothwell, April 2011", "exhibit_image" => "bothwell_castle.jpg", "photographer" => "LPK"),
                    array("exhibit_id" => "10", "exhibit_title" => "Hampden Park", "exhibit_description" => "Glasgow, June 2007 - SQA Event", "exhibit_image" => "hampden.jpg", "photographer" => "MLG"),
                    array("exhibit_id" => "11", "exhibit_title" => "Hogganfield Loch, Glasgow, Winter", "exhibit_description" => "Glasgow, January 2010", "exhibit_image" => "hogganfield_loch.jpg", "photographer" => "MLG"),
                    array("exhibit_id" => "16", "exhibit_title" => "Ramblas", "exhibit_description" => "Barcelona, July 1999 - Ramblas (Two Old Friends from Glasgow)", "exhibit_image" => "ramblas.jpg", "photographer" => "MLG"),
                    array("exhibit_id" => "17", "exhibit_title" => "River Clyde at Bothwell", "exhibit_description" => "Bothwell, April 2011 - River Clyde from Bothwell", "exhibit_image" => "river_clyde.jpg", "photographer" => "LPK"),
                    array("exhibit_id" => "18", "exhibit_title" => "River Kelvin", "exhibit_description" => "Glasgow, July 2011", "exhibit_image" => "river_kelvin.jpg", "photographer" => "MLG"),
                    array("exhibit_id" => "21", "exhibit_title" => "University Avenue", "exhibit_description" => "Glasgow, July 2011", "exhibit_image" => "university_avenue.jpg", "photographer" => "LPK")                                                                     
                ),
                "locations" => array(
                    array("location_id" => "1", "location_name" => "Kelvingrove Art Gallery and Museum", "location_postcode" => "G3 8AG"),
                    array("location_id" => "2", "location_name" => "Scottish National Gallery", "location_postcode" => "EH2 2EL"),
                    array("location_id" => "3", "location_name" => "Walker Art Gallery", "location_postcode" => "L3 8EL"),
                    array("location_id" => "4", "location_name" => "The Lowry", "location_postcode" => "M50 3AZ"),
                    array("location_id" => "5", "location_name" => "Tate Modern", "location_postcode" => "SE1 9TG")
                )                                                   
            ),
            array("exhibition_id" => "4", "exhibition_title" => "Some Churches", "exhibition_subject" => "Religious Architecture", "ticket_price" => "5",
                "exhibits" => array(
                    array("exhibit_id" => "1", "exhibit_title" => "Big Ben", "exhibit_description" => "London, September 2011", "exhibit_image" => "big_ben.jpg", "photographer" => "LPK"),
                    array("exhibit_id" => "12", "exhibit_title" => "Louvre, Paris", "exhibit_description" => "Paris, June 1998", "exhibit_image" => "louvre.jpg", "photographer" => "LPK"),
                    array("exhibit_id" => "19", "exhibit_title" => "Sagrada Familia - Honeymoon", "exhibit_description" => "Barcelona, June 1997 - Honeymoon", "exhibit_image" => "sagrada.jpg", "photographer" => "MLG"),
                    array("exhibit_id" => "20", "exhibit_title" => "Mormon Temple", "exhibit_description" => "Salt Lake City, July 2005", "exhibit_image" => "salt_lake.jpg", "photographer" => "MLG")                                                                      
                ),
                "locations" => array(
                    array("location_id" => "1", "location_name" => "Kelvingrove Art Gallery and Museum", "location_postcode" => "G3 8AG"),
                    array("location_id" => "2", "location_name" => "Scottish National Gallery", "location_postcode" => "EH2 2EL")
                )                                                   
            ),
            array("exhibition_id" => "5", "exhibition_title" => "Barcelona Highlights", "exhibition_subject" => "Barcelona", "ticket_price" => "15",
                "exhibits" => array(
                    array("exhibit_id" => "4", "exhibit_title" => "Martin at Camp Nou, Honeymoon", "exhibit_description" => "Barcelona, June 1997 - Honeymoon", "exhibit_image" => "campnou.jpg", "photographer" => "LPK"),
                    array("exhibit_id" => "5", "exhibit_title" => "Placa de Catalunya, Barcelona - Honeymoon", "exhibit_description" => "Barcelona, June 1997 - Honeymoon", "exhibit_image" => "catalunya.jpg", "photographer" => "MLG")
                ),
                "locations" => array(
                    array("location_id" => "3", "location_name" => "Walker Art Gallery", "location_postcode" => "L3 8EL"),
                    array("location_id" => "4", "location_name" => "The Lowry", "location_postcode" => "M50 3AZ"),
                    array("location_id" => "5", "location_name" => "Tate Modern", "location_postcode" => "SE1 9TG")
                )                                                   
            ),
            array("exhibition_id" => "6", "exhibition_title" => "Martin’s Pictures", "exhibition_subject" => "Martin", "ticket_price" => "5",
                "exhibits" => array(
                    array("exhibit_id" => "8", "exhibit_title" => "David Crosby at David Gilmour gig", "exhibit_description" => "Glasgow, May 2006", "exhibit_image" => "davidcrosby.jpg", "photographer" => "MLG"),
                    array("exhibit_id" => "22", "exhibit_title" => "Wolves", "exhibit_description" => "Yellowstone Park, October 2004", "exhibit_image" => "wolves.jpg", "photographer" => "MLG")
                ),
                "locations" => array(
                    array("location_id" => "1", "location_name" => "Kelvingrove Art Gallery and Museum", "location_postcode" => "G3 8AG"),
                    array("location_id" => "3", "location_name" => "Walker Art Gallery", "location_postcode" => "L3 8EL"),
                    array("location_id" => "4", "location_name" => "The Lowry", "location_postcode" => "M50 3AZ"),
                    array("location_id" => "5", "location_name" => "Tate Modern", "location_postcode" => "SE1 9TG")
                )
            )               
    );
    echo json_encode($exhibitionsarray);
?>

我确信json.exhibits.length 可以解决问题，但这会导致一些错误，例如json 和length 都未定义，所以我知道我的错误就在这里。我已经完成了一段类似的代码并遵循相同的修复但没有成功。

编辑：json 解析

function jsonAll()
{
    console.log("in function!");
    url = "exhibitions.php";
    xmlhttp.onreadystatechange = function() {
    if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
        console.log("the connection is complete");
        json = JSON.parse(xmlhttp.responseText);
        console.log(json);
        getExibitions();
}
    }

    xmlhttp.open("GET", url, true);
xmlhttp.send();
}

Answer 1

您的问题有点难以理解，但我认为问题在于您没有正确地遍历 JSON 数据。

var exhibition = json[i]; var exhibit = json[i].exhibits[j];

因此您可能需要第二个 for 循环

Answer 2

如果你想得到所有的展品，你需要两个循环：

for (var i = 0; i < json.length; i++) {
    for (var j = 0; j < json[i].exhibits.length; j++) {
        listCheck = document.createElement('src');
        listCheck.id = "<img src = " + "./images/" + json[i].exhibits[j].exhibit_image;
        myExhibitionsView.appendChild(option);
        option.appendChild(listCheck);
    }
}