JavaScript判断PDF与图片是否可以预览

function checkImageAccessibility(url, callback) {
  var img = new Image();
 
  img.onload = function() {
    callback(true); // 图片可以访问
  };
 
  img.onerror = function() {
    callback(false); // 图片无法访问
  };
 
  img.src = url;
}
 
// 使用示例
checkImageAccessibility('https://example.com/image.jpg', function(accessible) {
  console.log('图片可访问性：', accessible ? '是' : '否');
});

    pdfPreview(fileUrl) {
      this.loading = true;
      axios({
        url: fileUrl,
        method: 'GET',
        responseType: 'blob',
      }).then((res) => {
        if (res.status !== 200) return;
        setTimeout(() => {
          this.loading = false;
        }, 300);
        this.pdfContainerVisible = true;
        this.$nextTick(() => {
          let url = '';
          if (fileUrl.startsWith('http://')) {
            url = fileUrl.substring(5);
          } else if (fileUrl.startsWith('https://')) {
            url = fileUrl.substring(6);
          } else {
            url = fileUrl;
          }
          PDFObject.embed(url, '#pdf-container', {
            width: '100%'
          });
        });
      }).catch(() => {
        this.loading = false;
        this.otherVisible = true;
      });
    },