替换用户头像

Question

有这么一个需求，要求用户可以更换显示的头像。我的想法是这样的：用户先上传头像图片，替换服务器上的头像图片，然后刷新就是显示更新后的图片了。
问题是，JS怎么实现上传图片到服务器上，结合php或者Nodejs

Answer 1

写个上传文件的的表单即可<form&nbsp;action="upload.php"&nbsp;method="post"&nbsp;enctype="multipart/form-data"> <input&nbsp;type="file"&nbsp;name="file"&nbsp;id="file"&nbsp;/> <input&nbsp;type="submit"&nbsp;name="submit"&nbsp;value="Submit"&nbsp;/> </form>再写个处理文件的php<?phpif ((($_FILES["file"]["type"] == "image/gif")|| ($_FILES["file"]["type"] == "image/jpeg")|| ($_FILES["file"]["type"] == "image/pjpeg"))&& ($_FILES["file"]["size"] < 20000))&nbsp; {&nbsp; if ($_FILES["file"]["error"] > 0)&nbsp; &nbsp; {&nbsp; &nbsp; echo "Return Code: " . $_FILES["file"]["error"] . "<br />";&nbsp; &nbsp; }&nbsp; else&nbsp; &nbsp; {&nbsp; &nbsp; echo "Upload: " . $_FILES["file"]["name"] . "<br />";&nbsp; &nbsp; echo "Type: " . $_FILES["file"]["type"] . "<br />";&nbsp; &nbsp; echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";&nbsp; &nbsp; echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";&nbsp; &nbsp; if (file_exists("upload/" . $_FILES["file"]["name"]))&nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; echo $_FILES["file"]["name"] . " already exists. ";&nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; else&nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; move_uploaded_file($_FILES["file"]["tmp_name"],&nbsp; &nbsp; &nbsp; "upload/" . $_FILES["file"]["name"]);&nbsp; &nbsp; &nbsp; echo "Stored in: " . "upload/" . $_FILES["file"]["name"];&nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }&nbsp; }else&nbsp; {&nbsp; echo "Invalid file";&nbsp; }?>