Example of implementing avatar upload preview function in PHP
php avatar upload with preview:
Everyone is familiar with uploading pictures. However, in future projects, you may not be allowed to upload pictures using the submit refresh page method, such as uploading According to common sense, the avatar must be uploaded after selecting the photo in the album, and it will definitely not be uploaded through the form and click submit to refresh. I will introduce to you two asynchronous non-refresh upload pictures + picture preview: the first one is to upload through the ready-made uploadfy plug-in, there are many examples on the Internet. But what I will focus on introducing to you is the second method, uploading images through Ajax. Because using the uploadfy plug-in requires the device to support Flash in swf format, the first method cannot be used for most mobile phones. First of all, let me tell you about the upload principle: control the file text field through js. After selecting the photo, submit the form asynchronously through Ajax, and then use the position of the image as the return value, and use js to set the src attribute of img. Set as return value.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<link href="bootstrap-3.3.7-dist/css/bootstrap.min.css" rel="stylesheet" type="text/css" />
<script src="bootstrap-3.3.7-dist/js/jquery-1.11.2.min.js"></script>
<script src="bootstrap-3.3.7-dist/js/bootstrap.min.js"></script>
<style type="text/css">
#yl{ width:200px; height:200px; background-image:url(img/avatar.png); background-size:200px 200px;}
#file{ width:200px; height:200px; float:left; opacity:0;}
.modal-content{ width:500px;}
.kk{ margin-left:130px;}
</style>
</head>
<body>
<!-- 按钮触发模态框 -->
<button class="btn btn-primary btn-lg" data-toggle="modal" data-target="#myModal">
上传头像
</button>
<!-- 模态框（Modal） -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">
×
</button>
<h4 class="modal-title" id="myModalLabel">
上传头像
</h4>
</div>
<div class="modal-body">
<form id="sc" action="upload.php" method="post" enctype="multipart/form-data" target="shangchuan">
<input type="hidden" name="tp" value="" id="tp" />
<div id="yl" class="kk">
<input type="file" name="file" id="file" onchange="document.getElementById('sc').submit()" />
</div>
</form>
<iframe style="display:none" name="shangchuan" id="shangchuan">
</iframe>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">关闭
</button>
<!--<button type="button" class="btn btn-primary">
提交更改
</button>-->
</div>
</div><!-- /.modal-content -->
</div><!-- /.modal -->
</div>
</body>
<script type="text/javascript">
//回调函数,调用该方法传一个文件路径，该变背景图
function showimg(url)
{
var div = document.getElementById("yl");
div.style.backgroundImage = "url("+url+")";
document.getElementById("tp").value = url;
}
</script>
</html><?php
if($_FILES["file"]["error"])
{
echo $_FILES["file"]["error"];
}
else
{
if(($_FILES["file"]["type"]=="image/jpeg" || $_FILES["file"]["type"]=="image/png")&& $_FILES["file"]["size"]<1024000000)
{
$fname = "./img/".date("YmdHis").$_FILES["file"]["name"];
$filename = iconv("UTF-8","gb2312",$fname);
if(file_exists($filename))
{
echo "<script>alert('该文件已存在！');</script>";
}
else
{
move_uploaded_file($_FILES["file"]["tmp_name"],$filename);
unlink($_POST["tp"]);
echo "<script>parent.showimg('{$fname}');</script>";
}
}
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