Javascript-js upload the file, using the Formdata object, if you set the Setrequesetheader, will fail?

   formdata.append('images',type);   var xhr=new XMLHttpRequest();       xhr.open('post',path,true);     // xhr.setRequestHeader('content-type','multipart/form-data'); 若这儿一旦设置就会上传失败，这是怎么回事？难道是类型设置错误？       xhr.send(formdata);       xhr.onreadystatechange=function(){         if (this.readyState===4 && this.status===200)          {            if (this.responseText)             {              var data=this.responseText;              console.log(this.responseText);             }          }       }

Reply content:

   formdata.append('images',type);   var xhr=new XMLHttpRequest();       xhr.open('post',path,true);     // xhr.setRequestHeader('content-type','multipart/form-data'); 若这儿一旦设置就会上传失败，这是怎么回事？难道是类型设置错误？       xhr.send(formdata);       xhr.onreadystatechange=function(){         if (this.readyState===4 && this.status===200)          {            if (this.responseText)             {              var data=this.responseText;              console.log(this.responseText);             }          }       }

You send formdata do not need to set the header when you use the Send form-data , set up the problem instead.

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