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Ajax & PHP 边学边练 之五 图片处理

2009-12-02 09:13 543 查看
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:



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"><htmlxmlns="http://www.w3.org/1999/xhtml"><head><scripttype="text/javascript"src="functions.js"></script></head><body><!-- 显示图片 --><imgsrc="<?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
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