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How to implement the function of uploading pictures in php
- GuanhuiOriginal
- 2020-05-09 15:14:502908browse
How to implement the function of uploading pictures in php
First create a php script file; then use "$_FILES" to get the uploaded pictures; then Call the "move_uploaded_file()" function to save the image; finally create a form on the front-end page and submit the image.
Front-end:
<!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>文件上传</title>
</head>
<body>
<h1>文件上传</h1>
<div id="divPreview">
<img id="imgHeadPhoto" src="noperson.jpg" style="width: 160px; height: 170px; border: solid 1px #d2e2e2;"
alt="" />
</div>
<!--enctype 属性规定在发送到服务器之前应该如何对表单数据进行编码,"multipart/form-data"在使用包含文件上传控件的表单时，必须使用该值。-->
<form action="upload.php" method="post" enctype="multipart/form-data">
<!--file定义输入字段和 "浏览"按钮，供文件上传。-->
<input type="file" name="file" onchange="PreviewImage(this,'imgHeadPhoto','divPreview');" size="20" />
<input type="submit" value="上传"/>
</form>
</body>
<script type="text/javascript">
//js本地图片预览，兼容ie[6-9]、火狐、Chrome17+、Opera11+、Maxthon3
function PreviewImage(fileObj, imgPreviewId, divPreviewId) {
var allowExtention = ".jpg,.bmp,.gif,.png"; //允许上传文件的后缀名document.getElementById("hfAllowPicSuffix").value;
var extention = fileObj.value.substring(fileObj.value.lastIndexOf(".") + 1).toLowerCase();
var browserVersion = window.navigator.userAgent.toUpperCase();
if (allowExtention.indexOf(extention) > -1) {
if (fileObj.files) {//HTML5实现预览，兼容chrome、火狐7+等
if (window.FileReader) {
var reader = new FileReader();
reader.onload = function (e) {
document.getElementById(imgPreviewId).setAttribute("src", e.target.result);
}
reader.readAsDataURL(fileObj.files[0]);
} else if (browserVersion.indexOf("SAFARI") > -1) {
alert("不支持Safari6.0以下浏览器的图片预览!");
}
} else if (browserVersion.indexOf("MSIE") > -1) {
if (browserVersion.indexOf("MSIE 6") > -1) {//ie6
document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
} else {//ie[7-9]
fileObj.select();
if (browserVersion.indexOf("MSIE 9") > -1)
fileObj.blur(); //不加上document.selection.createRange().text在ie9会拒绝访问
var newPreview = document.getElementById(divPreviewId + "New");
if (newPreview == null) {
newPreview = document.createElement("div");
newPreview.setAttribute("id", divPreviewId + "New");
newPreview.style.width = document.getElementById(imgPreviewId).width + "px";
newPreview.style.height = document.getElementById(imgPreviewId).height + "px";
newPreview.style.border = "solid 1px #d2e2e2";
}
newPreview.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale',src='" + document.selection.createRange().text + "')";
var tempDivPreview = document.getElementById(divPreviewId);
tempDivPreview.parentNode.insertBefore(newPreview, tempDivPreview);
tempDivPreview.style.display = "none";
}
} else if (browserVersion.indexOf("FIREFOX") > -1) {//firefox
var firefoxVersion = parseFloat(browserVersion.toLowerCase().match(/firefox\/([\d.]+)/)[1]);
if (firefoxVersion < 7) {//firefox7以下版本
document.getElementById(imgPreviewId).setAttribute("src", fileObj.files[0].getAsDataURL());
} else {//firefox7.0+
document.getElementById(imgPreviewId).setAttribute("src", window.URL.createObjectURL(fileObj.files[0]));
}
} else {
document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
}
} else {
alert("仅支持" + allowExtention + "为后缀名的文件!");
fileObj.value = ""; //清空选中文件
if (browserVersion.indexOf("MSIE") > -1) {
fileObj.select();
document.selection.clear();
}
fileObj.outerHTML = fileObj.outerHTML;
}
return fileObj.value; //返回路径
}
</script>
</html> Back-end:
<?php
//var_dump($_FILES["file"]);
//array(5) { ["name"]=> string(17) "56e79ea2e1418.jpg" ["type"]=> string(10) "image/jpeg" ["tmp_name"]=> string(43) "C:\Users\asus\AppData\Local\Temp\phpD07.tmp" ["error"]=> int(0) ["size"]=> int(454445) }
//1.限制文件的类型，防止注入php或其他文件，提升安全
//2.限制文件的大小，减少内存压力
//3.防止文件名重复，提升用户体验
//方法一： 修改文件名 一般为:时间戳+随机数+用户名
// 方法二:建文件夹
//4.保存文件
//判断上传的文件是否出错,是的话，返回错误
if($_FILES["file"]["error"])
{
echo $_FILES["file"]["error"];
}
else
{
//没有出错
//加限制条件
//判断上传文件类型为png或jpg且大小不超过1024000B
if(($_FILES["file"]["type"]=="image/png"||$_FILES["file"]["type"]=="image/jpeg")&&$_FILES["file"]["size"]<1024000)
{
//防止文件名重复
$filename ="./img/".time().$_FILES["file"]["name"];
//转码，把utf-8转成gb2312,返回转换后的字符串， 或者在失败时返回 FALSE。
$filename =iconv("UTF-8","gb2312",$filename);
//检查文件或目录是否存在
if(file_exists($filename))
{
echo"该文件已存在";
}
else
{
//保存文件, move_uploaded_file 将上传的文件移动到新位置
move_uploaded_file($_FILES["file"]["tmp_name"],$filename);//将临时地址移动到指定地址
}
}
else
{
echo"文件类型不对";
}
} Recommended tutorial: "PHP Tutorial"
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