Ajax & PHP 边学边练 之五 图片处理

       在上一篇中讲解了如何通过Ajax提交表单并由PHP处理底层数据,本篇将主要介绍图片的上传与处理。对于文件的上传很简单,只需一个Form便可实现,再通过PHP将源文件上传到目标目录。先上个效果图:

upload

Sample6_1.php 中创建Form:

//显示上传状态和图片
<div id="showimg"></div>
//上传文件需要定义enctype,为了显示图片将target设为uploadframe
<form id="uploadform" action="process_upload.php" method="post" 
      enctype="multipart/form-data" target="uploadframe">
 Upload a File:<br />
 <input type="file" id="myfile" name="myfile" />
 //上传文件 
 <input type="submit" value="Submit" 
onclick="uploadimg(document.getElementById('uploadform')); return false;" /> <iframe id="uploadframe" name="uploadframe"
src="process_upload.php" class="noshow"></iframe> </form>

上传图片函数 uploadimg:

function uploadimg(theform){
 //提交Form
 theform.submit();
 //在showimg <div>中显示上传状态
 setStatus ("Loading...","showimg");
}
//上传状态函数
function setStatus (theStatus, theObj){
 obj = document.getElementById(theObj);
 if (obj){
  obj.innerHTML = "<div class=\"bold\">" + theStatus + "</div>";
 }
}

process_upload.php 提供文件上传功能:

<?php
//提供图片类型校验
$allowedtypes = array("image/jpeg","image/pjpeg","image/png",
"image/x-png","image/gif"); //文件存放目录 $savefolder = "images"; //如果有文件上传就开始干活 if (isset ($_FILES['myfile'])){ //检查上传文件是否符合$allowedtypes类型 if (in_array($_FILES['myfile']['type'],$allowedtypes)){ if ($_FILES['myfile']['error'] == 0){ $thefile = "$savefolder/".$_FILES['myfile']['name']; //通过move_uploaded_file上传文件 if (!move_uploaded_file($_FILES['myfile']['tmp_name'], $thefile)){ echo "There was an error uploading the file."; } else{ ?> <!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> <script type="text/javascript" src="functions.js"></script> </head> <body> <!-- 显示图片 --> <img src="<?php echo $thefile; ?>"
onload="doneloading(parent,'<?php echo $thefile; ?>')" /> </body> </html> <?php } } } } ?>

       上面代码最后部分的doneloading 函数就是用来显示图片及修改图片尺寸大小。其中会用到thumb.php,它会在images目录中生成出源图片的大、中、小三个尺寸,有兴趣可以研究一下。欢迎大家拍砖~

源代码下载

原文地址:https://www.cnblogs.com/gnielee/p/1615022.html