javascript - 模态未定义

Question

我试图在页面打开时制作模式提示，我希望它显示图像。由于某种原因，它一直告诉我图像未定义，当我将它与 onlick 函数一起使用时，它显示正常。我正在使用 W3School 脚本的修改版本。有任何想法吗？提前致谢!代码:

          HTML:                  
                            <img id="myImg" src="http://192.185.4.115/~hitclubar/images/prueba.png" alt="" width="300" height="200" style="display:none;">

                             <!--The Modal --> 
                            <div id="myModal" class="modal">
                              <a href="http://facebook.com/Hitclubar">   Click Evento Facebook </a>
                              <span class="close">×</span>
                              <img class="modal-content" id="img01">
                              <div id="caption"></div>
                            </div> 

Javascript:

// Get the modal
var modal = document.getElementById('myModal');

// Get the image and insert it inside the modal - use its "alt" text as a caption
var img = document.getElementById('myImg');
var modalImg = document.getElementById("img01");
var captionText = document.getElementById("caption");


$(function(){ 
modal.style.display = "block";
modalImg.src = document.getElementById('myImg');
modalImg.alt = "HOLA";
captionText.innerHTML = "HOLA";
});


// Get the <span> element that closes the modal
var span = document.getElementsByClassName("close")[0];

// When the user clicks on <span> (x), close the modal
span.onclick = function() {
modal.style.display = "none";
}

CSS:

#myImg {
                        border-radius: 5px;
                        cursor: pointer;
                        transition: 0.3s;
                }

                #myImg:hover {opacity: 0.7;}

                /* The Modal (background) */
                .modal {
                        display: none; /* Hidden by default */
                        position: fixed; /* Stay in place */
                        z-index: 1; /* Sit on top */
                        padding-top: 100px; /* Location of the box */
                        left: 0;
                        top: 0;
                        width: 100%; /* Full width */
                        height: 100%; /* Full height */
                        overflow: auto; /* Enable scroll if needed */
                        background-color: rgb(0,0,0); /* Fallback color */
                        background-color: rgba(0,0,0,0.9); /* Black w/ opacity */
                 }

                 /* Modal Content (image) */
                 .modal-content {
                        margin: auto;
                        display: block;
                        width: 80%;
                        max-width: 700px;
                 }

                 /* Caption of Modal Image */
                 #caption {
                        margin: auto;
                        display: block;
                        width: 80%;
                        max-width: 700px;
                        text-align: center;
                        color: #ccc;
                        padding: 10px 0;
                        height: 170px;
                  }

                  /* Add Animation */
                  .modal-content, #caption {
                        -webkit-animation-name: zoom;
                        -webkit-animation-duration: 0.6s;
                        animation-name: zoom;
                        animation-duration: 0.6s;
                  }

                  @-webkit-keyframes zoom {
                        from {-webkit-transform:scale(0)}
                        to {-webkit-transform:scale(1)}
                  }

                  @keyframes zoom {
                        from {transform:scale(0)}
                        to {transform:scale(1)}
                  }

                  /* The Close Button */
                  .close {
                        position: absolute;
                        top: 15px;
                        right: 35px;
                        color: #f1f1f1;
                        font-size: 40px;
                        font-weight: bold;
                        transition: 0.3s;
                  }

                  .close:hover,
                  .close:focus {
                        color: #bbb;
                        text-decoration: none;
                        cursor: pointer;
                  }

                  /* 100% Image Width on Smaller Screens */
                  @media only screen and (max-width: 700px){
                 .modal-content {
                        width: 100%;
                        }
                  } 

Answer 1

您放置了

var modal = document.getElementById('myModal');

位于脚本的开头。这样，脚本会尝试在页面加载期间尽早获取模式(由于模式尚不存在而失败)。

尝试这样:

$(function() {
    // Get the modal
    var modal = document.getElementById('myModal');

    // Get the image and insert it inside the modal - use its "alt" text as a caption
    var img = document.getElementById('myImg');
    var modalImg = document.getElementById("img01");
    var captionText = document.getElementById("caption"); 

    modal.style.display = "block";
    modalImg.src = document.getElementById('myImg');
    modalImg.alt = "HOLA";
    captionText.innerHTML = "HOLA";
});

现在，当页面完全加载 html 时，模式就会被引用，并且它应该可以工作。