JavaScript cross-domain issues

The content shared with you in this article is the cross-domain issue of JavaScript, which has certain reference value. Friends in need can refer to it

1jsonp

General interfaces use jsonp cross-domain , use jquery's ajax to specify the dataType as jsonp

$.ajax({
                async : true,
                url : "https://api.douban.com/v2/book/search",
                type : "GET",
                dataType : "jsonp", // 返回的数据类型，设置为JSONP方式
                jsonp : 'callback', //指定一个查询参数名称来覆盖默认的 jsonp 回调参数名 callback
                jsonpCallback: 'handleResponse', //设置回调函数名
                data : {
                    q : "javascript",
                    count : 1
                },
                success: function(response, status, xhr){
                    console.log('状态为：' + status + ',状态是：' + xhr.statusText);
                    console.log(response);
                }
            });

The principle of jsonp supporting cross-domain requests: The principle of JSONP implementing cross-domain requests is simply to dynamically create the <script> tag, and then use <script&gt ;'s src is not subject to the same-origin policy to obtain data across domains. </script>

In fact, the following code is implemented: the js script returns callback (data), and a callback function is defined in the page

<script type="text/javascript">
    function handleResponse(response){
            console.log(response);
    }
</script>
<script type="text/javascript">
    window.onload = function() {

    var oBtn = document.getElementById(&#39;btn&#39;);

    oBtn.onclick = function() {     

        var script = document.createElement("script");
        script.src = "https://api.douban.com/v2/book/search?q=javascript&count=1&callback=handleResponse";
        document.body.insertBefore(script, document.body.firstChild);   
    };
};
</script>

2iframe form is compatible with IE browser, and the body content of the iframe It is the data to be used

<iframe name=&#39;hidden_frame&#39; id="hidden_frame" style=&#39;display:none&#39;></iframe>
        <form id="fileform" method="post" enctype="multipart/form-data" target="hidden_frame">
            <input type="file" name="fileUpload" />
        </form>
        <button id="submitbtn">开始上传</button>
        <script type="text/javascript">
            function callback(msg) {
                //回调函数
                alert(msg);
            }
        </script>
        <script type="text/javascript">
            $("#submitbtn").click(function() {
                var callbackurl = window.location.href.substring(0, window.location.href.lastIndexOf(&#39;/&#39;)) + "proxy.html"; //获取代理文件路径
                $("#fileform").attr("action", "FileHandler.ashx?callbackurl=" + callbackurl);
                $("#fileform").submit();
            })
        </script>

3H5’s postMessage() method, the compatibility is not that good

For details, please seehttps://www.cnblogs.com/dolphinX/ p/3464056.html

Upload image code, the data returned by the interface is how postMessage is written

<form action=&#39;http://bird.sns.iqiyi.com/group_photo/upload&#39; method="post" target="imgFile"
    id="fileinfo" enctype="multipart/form-data">
      <input type="file" id="imgFile" accept="image/gif, image/png" class="hide" onchange="getPhotoSize(this)"
      />
      <input type="hidden" name="name" value="" />
      <input type="hidden" name="hobby" value="" />
    </form>
    <iframe

<script type="text/javascript">
    $(document).ready(function() {
      $(&#39;#upload&#39;).click(function() {
        $("#imgFile")[0].click();
      });
    });
    var queryToJson = function(url) {
      url = url.replace(/#.*/, "");
      var query = url.substr(url.lastIndexOf(&#39;?&#39;) + 1);
      var params = query.split(&#39;&&#39;);
      var result = {};
      for (var i = 0; i < params.length; i++) {
        var t = params[i].split("=");
        if (!t[0]) continue;
        result[decodeURIComponent(t[0])] = decodeURIComponent(t[1] || "");
      }
      return result;
    };
    $(&#39;[name=name]&#39;).val(queryToJson(window.location.href).name);
    $(&#39;[name=hobby]&#39;).val(queryToJson(window.location.href).hobby);
    //判断照片大小
    function getPhotoSize(obj) {
      photoExt = obj.value.substr(obj.value.lastIndexOf(".")).toLowerCase(); 
      //只支持jpg,png
      if (photoExt != &#39;.jpg&#39; && photoExt != &#39;.png&#39;) {
        showMsg("请上传正确的图片格式，如JPEG、PNG");
        return false;
      }
      var fileSize = 0;
      fileSize = obj.files[0].size;
      fileSize = Math.round(fileSize / 1024); //单位为KB
      if (fileSize >= 10000) {
        showMsg("建议上传图片不超过10M");
        return false;
      }
      //跳转到过渡页，请求上传接口,将接口返回插入结果页src
      $(&#39;#page2&#39;).addClass(&#39;hide&#39;);
      $(&#39;#imgFile&#39;).addClass(&#39;hide&#39;);
      $(&#39;#fileinfo&#39;).submit();
      $(&#39;#loading&#39;).removeClass(&#39;hide&#39;);
      getMsg();
    }
    //获取返回数据
    function getMsg() {
      window.addEventListener(&#39;message&#39;,
      function(e) {
        $(&#39;#loading&#39;).addClass(&#39;hide&#39;);
        if (e.source != window.parent) return;
        if (e.data.code == &#39;A00000&#39;) {
          $(&#39;#imgSrc&#39;)[0].src = e.data.data.url;
          $(&#39;#msg&#39;).html(e.data.data.message);
          $(&#39;#page5&#39;).removeClass(&#39;hide&#39;);
        } else {
          location.href = &#39;/anotherTry.html&#39;;
        }
      },
      false);
    }
    //显示提示信息
    function showMsg(msg) {
      var _this = this;
      $(&#39;#msgTip&#39;).html(msg);
      $(&#39;#msgTip&#39;).removeClass(&#39;hide&#39;);
      window.setTimeout(function() {
        $(&#39;#msgTip&#39;).addClass(&#39;hide&#39;);
      },
      3000);
    }
    //再试一次
    function tryAgain() {
      $(&#39;#fileinfo&#39;).submit();
      $(&#39;#page5&#39;).addClass(&#39;hide&#39;);
      //看不到加载页面，页面闪
      $(&#39;#loading&#39;).removeClass(&#39;hide&#39;);
      getMsg();
    }
  </script>

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