如何使用Javasript和RestAPI为SharePoint online上传文件？

使用JavaScript和RestAPI为SharePoint Online上传文件的步骤如下：

引入SharePoint JavaScript库和jQuery库：在HTML文件中添加以下代码，用于引入所需的JavaScript库。

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/sharepointplus/3.0.14/sharepointplus.js"></script>

创建HTML表单：创建一个HTML表单，包含一个文件选择输入字段和一个上传按钮。

<form>
  <input type="file" id="fileInput" />
  <button type="button" id="uploadButton">上传</button>
</form>

编写JavaScript代码：使用JavaScript编写处理文件上传的代码。

$(document).ready(function() {
  $("#uploadButton").click(function() {
    var fileInput = document.getElementById('fileInput');
    var file = fileInput.files[0];
    var serverUrl = "https://your-sharepoint-site-url/_api/web/lists/getByTitle('Documents')/RootFolder/Files/add(url='" + file.name + "', overwrite=true)";
    
    uploadFileToSharePoint(serverUrl, file);
  });
});

function uploadFileToSharePoint(serverUrl, file) {
  var reader = new FileReader();
  reader.onloadend = function(evt) {
    if (evt.target.readyState == FileReader.DONE) {
      var buffer = evt.target.result;
      $.ajax({
        url: serverUrl,
        type: "POST",
        data: buffer,
        processData: false,
        headers: {
          "Accept": "application/json;odata=verbose",
          "X-RequestDigest": $("#__REQUESTDIGEST").val()
        },
        success: function(data) {
          console.log("文件上传成功！");
        },
        error: function(error) {
          console.log("文件上传失败：" + error);
        }
      });
    }
  };
  reader.readAsArrayBuffer(file);
}