如何从API中的Json数据中获取数据

Question

I would like to grab data which has a name tag by calling JSON data by using Ajax. But now a function showCard does not work correctly. How can I get the data which has a name tag? When you click a img which has found , I would like to grab data from an API, and show its name by innerHTML. But now nothing happens when you click it. ps Its id is added in the function populatePokedex . Hopefully, this question makes sense. Thanks.

(function() {
'use strict';

window.onload = function(){
    populatePokedex(); // <- This works correctly

    var $foundPics = document.getElementsByClassName("found");
    for(var i = 0; i < $foundPics.length; i++){
        $foundPics[i].onclick = showCard;
    }
};



// populate Pokedex
function populatePokedex() {

    var xhr = new XMLHttpRequest();
    xhr.open("GET", "https://webster.cs.washington.edu/pokedex/pokedex.php?pokedex=all");
    xhr.onload = function(){
        if (this.status == 200) {
            var picArr = this.responseText.split("\n");
            for(var i=0; i < picArr.length; i++){
                var eachName = picArr[i].split(":");
                var spriteurl = "/Pokedex/sprites/" + eachName[1];
                var imgClass = 'sprite';
                if(eachName[1]==='bulbasaur.png' || eachName[1]==='charmander.png' || eachName[1]==='squirtle.png'){
                    imgClass += ' found';
                } else {
                    imgClass += ' unfound';
                }
                document.getElementById("pokedex-view").innerHTML += "<img src=\"" + spriteurl + "\" id=\"" + eachName[0] + "\" class=\"" + imgClass + "\">";
            }
        } else {
            document.getElementById("pokedex-view").innerHTML = "ERROR: Status: " + this.status + ", " + this.statusText;
        }
    };
    xhr.onerror = function(){
        document.getElementById("pokedex-view").innerHTML = "ERROR";
    };
    xhr.send();
}


// if the pokemon is found, it shows the data of the pokemon
function showCard() {
    var xhr = new XMLHttpRequest();
    var url = "https://webster.cs.washington.edu/pokedex/pokedex.php?pokemon=" + this.id;
    xhr("GET", url);
    xhr.onload = function(){
        var data = JSON.parse(this.responseText);
        var pokeName = document.getElementsByClassName("name");
        for(var i=0; i < pokeName.length; i++){
            pokeName[i].innerHTML = data.name;
        }
    };
    xhr.onerror = function(){
        alert("ERROR");
    };
    xhr.send();

}


})();

Part of HTML is listed below;

  <div id="my-card">

    <div class="card-container">
      <div class="card">
        <h2 class="name">Pokemon Name</h2>
        <img src="icons/fighting.jpg" alt="weakness" class="weakness" />
      </div>
    </div>
  </div>

  <!-- You populate this using JavaScript -->
  <div id="pokedex-view"></div>

Answer 1

When I use your url: https://webster.cs.washington.edu/pokedex/pokedex.php?pokemon=mew , I got this data:

{"name":"Mew","hp":160,"info":{"id":"151","type":"psychic","weakness":"dark","description":"Its DNA is said to contain the genetic codes of all Pokemon."},"images":{"photo":"images\/mew.jpg","typeIcon":"icons\/psychic.jpg","weaknessIcon":"icons\/dark.jpg"},"moves":[{"name":"Amnesia","type":"psychic"},{"name":"Psychic","dp":90,"type":"psychic"}]}

Assuming you want to display the word mew, data.name or data['name'] works fine. What I'm suspecting is that document.getElementsByClassName("name").innerHTML does not exist or something along that line. Could I see the error message that appears when the function is run or show your HTML portion as well?

Answer 2

You have a few issues in you JS for showCard

I have coded a simple solution. I added some brief explanations in the code (as comments)

 (function() { 'use strict'; window.onload = function() { populatePokedex(); // <- This works correctly // adding event listeners to dynamically added nodes. document.querySelector('body').addEventListener('click', function(event) { // need to target only elements with class found (but unfound would also match the indexOf below, so we changed the name of the matching class slightly) if (event.target.className.toLowerCase().indexOf('founded') != -1) { showCard(); } }); }; // populate Pokedex function populatePokedex() { var xhr = new XMLHttpRequest(); xhr.open("GET", "https://webster.cs.washington.edu/pokedex/pokedex.php?pokedex=all"); xhr.onload = function() { if (this.status == 200) { var picArr = this.responseText.split("\\n"); for (var i = 0; i < picArr.length; i++) { var eachName = picArr[i].split(":"); var spriteurl = "https://webster.cs.washington.edu/pokedex/sprites/" + eachName[1]; var imgClass = 'sprite'; if (eachName[1] === 'bulbasaur.png' || eachName[1] === 'charmander.png' || eachName[1] === 'squirtle.png') { imgClass += ' founded'; } else { imgClass += ' unfound'; } document.getElementById("pokedex-view").innerHTML += "<img src=\\"" + spriteurl + "\\" id=\\"" + eachName[0] + "\\" class=\\"" + imgClass + "\\">"; } } else { document.getElementById("pokedex-view").innerHTML = "ERROR: Status: " + this.status + ", " + this.statusText; } }; xhr.onerror = function() { document.getElementById("pokedex-view").innerHTML = "ERROR"; }; xhr.send(); } // if the pokemon is found, it shows the data of the pokemon function showCard() { var xhr = new XMLHttpRequest(); // since you are in a click event, use the target's id instead var url = "https://webster.cs.washington.edu/pokedex/pokedex.php?pokemon=" + event.target.id; // there was an error here xhr.open("GET", url); xhr.onload = function() { // parse the response text into JSON var data = JSON.parse(this.responseText); // update the element with this id with a new value from the response data document.getElementById("pokemon-name").innerHTML = data.name; }; xhr.onerror = function() { alert("ERROR"); }; xhr.send(); } })(); 

 .founded:hover { cursor: pointer; } .founded { border: 1px solid green; } 

 <div id="my-card"> <div class="card-container"> <div class="card"> <h2 id="pokemon-name" class="name">Pokemon Name</h2> <img src="https://webster.cs.washington.edu/pokedex/icons/fighting.jpg" alt="weakness" class="weakness" /> </div> </div> </div> <!-- You populate this using JavaScript --> <div id="pokedex-view"></div> 

Answer 3

Rather than using the below to declare the "click"

$foundPics[i].onclick = showCard;

You should bind an event listener like this

$foundPics[i].addEventListener('click', showCard());

Aside from this you xhr.open() method is in the wrong place. The standard way of using it is to put it just before your send() call.

Hope this helps