JavaScript实现拖拽预览，AJAX小文件上传

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<p><strong>本地上传，提前预览（图片，视频）</strong></p>

<p>1.html中div标签预览显示，button标签触发上传事件。</p>

<p></p>

<div class="dp-highlighter bg_html"><div class="bar"><div class="tools"><b>[html]</b> <a href="#" class="ViewSource" title="view plain" onclick="dp.sh.Toolbar.Command('ViewSource',this);return false;" target="_blank">view plain</a><span data-mod="popu_168">
<a href="#" class="CopyToClipboard" title="copy" onclick="dp.sh.Toolbar.Command('CopyToClipboard',this);return false;" target="_blank">copy</a><div style="position: absolute; left: 465px; top: 564px; width: 18px; height: 18px; z-index: 99;"><embed id="ZeroClipboardMovie_1"
src="http://static.blog.csdn.net/scripts/ZeroClipboard/ZeroClipboard.swf" loop="false" menu="false" quality="best" bgcolor="#ffffff" name="ZeroClipboardMovie_1" allowscriptaccess="always" allowfullscreen="false" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer"
flashvars="id=1&width=18&height=18" wmode="transparent" width="18" height="18" align="middle"></div></span><span data-mod="popu_169"> <a href="#" class="PrintSource" title="print" onclick="dp.sh.Toolbar.Command('PrintSource',this);return false;" target="_blank">print</a></span><a
href="#" class="About" title="?" onclick="dp.sh.Toolbar.Command('About',this);return false;" target="_blank">?</a></div></div><ol start="1" class="dp-xml"><li class="alt"><span><span class="tag"><</span><span class="tag-name">div</span><span>  </span><span
class="attribute">id</span><span>=</span><span class="attribute-value">"drop_area"</span><span> </span><span class="attribute">style</span><span>=</span><span class="attribute-value">"border:3px dashed silver;width:200px; height:200px"</span><span
class="tag">></span><span>将图片拖拽到此</span><span class="tag"></</span><span class="tag-name">div</span><span class="tag">></span><span>  </span></span></li><li class=""><span><span class="tag"><</span><span class="tag-name">button</span><span> </span><span
class="attribute">onclick</span><span>=</span><span class="attribute-value">"xhr2()"</span><span class="tag">></span><span>ajax上传</span><span class="tag"></</span><span class="tag-name">button</span><span class="tag">></span><span>  </span></span></li></ol></div><pre
name="code" class="html" style="display: none;"><div  id="drop_area" style="border:3px dashed silver;width:200px; height:200px">将图片拖拽到此</div>

<button onclick="xhr2()">ajax上传</button></pre><br>

2.禁止浏览器打开文件行为<br>

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<p></p>

<div class="dp-highlighter bg_html"><div class="bar"><div class="tools"><b>[html]</b> <a href="#" class="ViewSource" title="view plain" onclick="dp.sh.Toolbar.Command('ViewSource',this);return false;" target="_blank">view plain</a><span data-mod="popu_168">
<a href="#" class="CopyToClipboard" title="copy" onclick="dp.sh.Toolbar.Command('CopyToClipboard',this);return false;" target="_blank">copy</a><div style="position: absolute; left: 465px; top: 739px; width: 18px; height: 18px; z-index: 99;"><embed id="ZeroClipboardMovie_2"
src="http://static.blog.csdn.net/scripts/ZeroClipboard/ZeroClipboard.swf" loop="false" menu="false" quality="best" bgcolor="#ffffff" name="ZeroClipboardMovie_2" allowscriptaccess="always" allowfullscreen="false" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer"
flashvars="id=2&width=18&height=18" wmode="transparent" width="18" height="18" align="middle"></div></span><span data-mod="popu_169"> <a href="#" class="PrintSource" title="print" onclick="dp.sh.Toolbar.Command('PrintSource',this);return false;" target="_blank">print</a></span><a
href="#" class="About" title="?" onclick="dp.sh.Toolbar.Command('About',this);return false;" target="_blank">?</a></div>&l
4000
t;/div><ol start="1" class="dp-xml"><li class="alt"><span><span>document.addEventListener("drop",function(e){  //拖离   </span></span></li><li
class=""><span>    e.preventDefault();      </span></li><li class="alt"><span>})  </span></li><li class=""><span>document.addEventListener("dragleave",function(e){  //拖后放   </span></li><li
class="alt"><span>    e.preventDefault();      </span></li><li class=""><span>})  </span></li><li class="alt"><span>document.addEventListener("dragenter",function(e){  //拖进  </span></li><li
class=""><span>    e.preventDefault();      </span></li><li class="alt"><span>})  </span></li><li class=""><span>document.addEventListener("dragover",function(e){  //拖来拖去    </span></li><li
class="alt"><span>    e.preventDefault();      </span></li><li class=""><span>})  </span></li></ol></div><pre name="code" class="html" style="display: none;">document.addEventListener("drop",function(e){ 
//拖离

    e.preventDefault();    

})

document.addEventListener("dragleave",function(e){  //拖后放

    e.preventDefault();    

})

document.addEventListener("dragenter",function(e){  //拖进

    e.preventDefault();    

})

document.addEventListener("dragover",function(e){  //拖来拖去  

    e.preventDefault();    

})</pre>

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</p>

3.拖拽,预览文件

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<p></p>

<div class="dp-highlighter bg_html"><div class="bar"><div class="tools"><b>[html]</b> <a href="#" class="ViewSource" title="view plain" onclick="dp.sh.Toolbar.Command('ViewSource',this);return false;" target="_blank">view plain</a><span data-mod="popu_168">
<a href="#" class="CopyToClipboard" title="copy" onclick="dp.sh.Toolbar.Command('CopyToClipboard',this);return false;" target="_blank">copy</a><div style="position: absolute; left: 465px; top: 1094px; width: 18px; height: 18px; z-index: 99;"><embed id="ZeroClipboardMovie_3"
src="http://static.blog.csdn.net/scripts/ZeroClipboard/ZeroClipboard.swf" loop="false" menu="false" quality="best" bgcolor="#ffffff" name="ZeroClipboardMovie_3" allowscriptaccess="always" allowfullscreen="false" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer"
flashvars="id=3&width=18&height=18" wmode="transparent" width="18" height="18" align="middle"></div></span><span data-mod="popu_169"> <a href="#" class="PrintSource" title="print" onclick="dp.sh.Toolbar.Command('PrintSource',this);return false;" target="_blank">print</a></span><a
href="#" class="About" title="?" onclick="dp.sh.Toolbar.Command('About',this);return false;" target="_blank">?</a></div></div><ol start="1" class="dp-xml"><li class="alt"><span><span>var </span><span class="attribute">box</span><span> = </span><span
class="attribute-value">document</span><span>.getElementById('drop_area'); //拖拽区域     </span></span></li><li class=""><span>box.addEventListener("drop",function(e){           </span></li><li
class="alt"><span>    var <span class="attribute">fileList</span><span> = </span><span class="attribute-value">e</span><span>.dataTransfer.files; //获取文件对象    </span></span></li><li class=""><span>    //检测是否是拖拽文件到页面的操作            </span></li><li
class="alt"><span>    if(<span class="attribute">fileList.length</span><span> == 0){                </span></span></li><li class=""><span>        return false;            </span></li><li
class="alt"><span>    }             </span></li><li class=""><span>    //拖拉图片到浏览器，可以实现预览功能    </span></li><li class="alt"><span>    //规定视频格式  </span></li><li
class=""><span>    <span class="attribute">Array.prototype.S</span><span>=</span><span class="attribute-value">String</span><span>.fromCharCode(2);  </span></span></li><li class="alt"><span>    <span class="attribute">Array.prototype.in_array</span><span>=</span><span
class="attribute-value">function</span><span>(e){  </span></span></li><li class=""><span>        var <span class="attribute">r</span><span>=</span><span class="attribute-value">new</span><span> RegExp(this.S+e+this.S);  </span></span></li><li
class="alt"><span>        return (r.test(this.S+this.join(this.S)+this.S));  </span></li><li class=""><span>    };  </span></li><li class="alt"><span>    var <span
class="attribute">video_type</span><span>=["video/mp4","video/ogg"];  </span></span></li><li class=""><span>      </span></li><li class="alt"><span>    //创建一个url连接,供src属性引用  </span></li><li
class=""><span>    var <span class="attribute">fileurl</span><span> = </span><span class="attribute-value">window</span><span>.URL.createObjectURL(fileList[0]);                </span></span></li><li
class="alt"><span>    if(fileList[0].type.indexOf('image') === 0){  //如果是图片  </span></li><li class=""><span>        var <span class="attribute">str</span><span>=</span><span
class="attribute-value">"<img width='200px' height='200px' src='"</span><span>+fileurl+"'</span><span class="tag">></span><span>";  </span></span></li><li class="alt"><span>        document.getElementById('drop_area')<span
class="attribute">.innerHTML</span><span>=</span><span class="attribute-value">str</span><span>;                   </span></span></li><li class=""><span>    }else if(video_type.in_array(fileList[0].type)){   //如果是规定格式内的视频                    </span></li><li
class="alt"><span>        var <span class="attribute">str</span><span>=</span><span class="attribute-value">"<video width='200px' height='200px' controls='controls' src='"</span><span>+fileurl+"'</span><span
class="tag">></span><span class="tag"></</span><span class="tag-name">video</span><span class="tag">></span><span>";  </span></span></li><li class=""><span>        document.getElementById('drop_area')<span
class="attribute">.innerHTML</span><span>=</span><span class="attribute-value">str</span><span>;        </span></span></li><li class="alt"><span>    }else{ //其他格式，输出文件名  </span></li><li
class=""><span>        //alert("不预览");  </span></li><li class="alt"><span>        var <span class="attribute">str</span><span>=</span><span class="attribute-value">"文件名字:"</span><span>+fileList[0].name;  </span></span></li><li
class=""><span>        document.getElementById('drop_area')<span class="attribute">.innerHTML</span><span>=</span><span class="attribute-value">str</span><span>;      </span></span></li><li
class="alt"><span>    }         </span></li><li class=""><span>    <span class="attribute">resultfile</span><span> = </span><span class="attribute-value">fileList</span><span>[0];             </span></span></li><li
class="alt"><span>},false);  </span></li></ol></div><pre name="code" class="html" style="display: none;">var box = document.getElementById('drop_area'); //拖拽区域   

box.addEventListener("drop",function(e){         

    var fileList = e.dataTransfer.files; //获取文件对象  

    //检测是否是拖拽文件到页面的操作          

    if(fileList.length == 0){              

        return false;          

    }           

    //拖拉图片到浏览器，可以实现预览功能  

    //规定视频格式

    Array.prototype.S=String.fromCharCode(2);

    Array.prototype.in_array=function(e){

        var r=new RegExp(this.S+e+this.S);

        return (r.test(this.S+this.join(this.S)+this.S));

    };

    var video_type=["video/mp4","video/ogg"];

    

    //创建一个url连接,供src属性引用

    var fileurl = window.URL.createObjectURL(fileList[0]);               

    if(fileList[0].type.indexOf('image') === 0){  //如果是图片

        var str="<img width='200px' height='200px' src='"+fileurl+"'>";

        document.getElementById('drop_area').innerHTML=str;                 

    }else if(video_type.in_array(fileList[0].type)){   //如果是规定格式内的视频                  

        var str="<video width='200px' height='200px' controls='controls' src='"+fileurl+"'></video>";

        document.getElementById('drop_area').innerHTML=str;      

    }else{ //其他格式，输出文件名

        //alert("不预览");

        var str="文件名字:"+fileList[0].name;

        document.getElementById('drop_area').innerHTML=str;    

    }        

    resultfile = fileList[0];            

},false);</pre><br>

4.ajax上传

<p></p>

<p></p>

<div class="dp-highlighter bg_html"><div class="bar"><div class="tools"><b>[html]</b> <a href="#" class="ViewSource" title="view plain" onclick="dp.sh.Toolbar.Command('ViewSource',this);return false;" target="_blank">view plain</a><span data-mod="popu_168">
<a href="#" class="CopyToClipboard" title="copy" onclick="dp.sh.Toolbar.Command('CopyToClipboard',this);return false;" target="_blank">copy</a><div style="position: absolute; left: 465px; top: 1791px; width: 18px; height: 18px; z-index: 99;"><embed id="ZeroClipboardMovie_4"
src="http://static.blog.csdn.net/scripts/ZeroClipboard/ZeroClipboard.swf" loop="false" menu="false" quality="best" bgcolor="#ffffff" name="ZeroClipboardMovie_4" allowscriptaccess="always" allowfullscreen="false" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer"
flashvars="id=4&width=18&height=18" wmode="transparent" width="18" height="18" align="middle"></div></span><span data-mod="popu_169"> <a href="#" class="PrintSource" title="print" onclick="dp.sh.Toolbar.Command('PrintSource',this);return
af01
false;" target="_blank">print</a></span><a
href="#" class="About" title="?" onclick="dp.sh.Toolbar.Command('About',this);return false;" target="_blank">?</a></div></div><ol start="1" class="dp-xml"><li class="alt"><span><span>function xhr2(){  </span></span></li><li class=""><span>    var <span
class="attribute">xhr</span><span> = </span><span class="attribute-value">new</span><span> XMLHttpRequest();//第一步  </span></span></li><li class="alt"><span>    //新建一个FormData对象  </span></li><li class=""><span>    var <span
class="attribute">formData</span><span> = </span><span class="attribute-value">new</span><span> FormData(); //++++++++++  </span></span></li><li class="alt"><span>    //追加文件数据  </span></li><li class=""><span>    formData.append('file', resultfile);  </span></li><li
class="alt"><span>    //post方式  </span></li><li class=""><span>    xhr.open('POST', 'xhr2.php'); //第二步骤  </span></li><li class="alt"><span>    //发送请求  </span></li><li
class=""><span>    xhr.send(formData);  //第三步骤  </span></li><li class="alt"><span>    //ajax返回  </span></li><li class=""><span>    <span class="attribute">xhr.onreadystatechange</span><span> = </span><span
class="attribute-value">function</span><span>(){ //第四步  </span></span></li><li class="alt"><span>　　　　if ( <span class="attribute">xhr.readyState</span><span> == 4 && </span><span
class="attribute">xhr.status</span><span> == 200 ) {  </span></span></li><li class=""><span>　　　　　　console.log( xhr.responseText );        </span></li><li
class="alt"><span>　　　　}  </span></li><li class=""><span>　　};  </span></li><li class="alt"><span>    //设置超时时间  </span></li><li class=""><span>    <span
class="attribute">xhr.timeout</span><span> = </span><span class="attribute-value">10000</span><span>;  </span></span></li><li class="alt"><span>    <span class="attribute">xhr.ontimeout</span><span> = </span><span
class="attribute-value">function</span><span>(event){  </span></span></li><li class=""><span>　　　　alert('请求超时！');  </span></li><li class="alt"><span>　　}           </span></li><li
class=""><span>}  </span></li></ol></div><pre name="code" class="html" style="display: none;">function xhr2(){

    var xhr = new XMLHttpRequest();//第一步

    //新建一个FormData对象

    var formData = new FormData(); //++++++++++

    //追加文件数据

    formData.append('file', resultfile);

    //post方式

    xhr.open('POST', 'xhr2.php'); //第二步骤

    //发送请求

    xhr.send(formData);  //第三步骤

    //ajax返回

    xhr.onreadystatechange = function(){ //第四步

　　　　if ( xhr.readyState == 4 && xhr.status == 200 ) {

　　　　　　console.log( xhr.responseText );        

　　　　}

　　};

    //设置超时时间

    xhr.timeout = 10000;

    xhr.ontimeout = function(event){

　　　　alert('请求超时！');

　　}            

}</pre><br>

5.php保存文件

<p></p>

<p></p>

<div class="dp-highlighter bg_html"><div class="bar"><div class="tools"><b>[html]</b> <a href="#" class="ViewSource" title="view plain" onclick="dp.sh.Toolbar.Command('ViewSource',this);return false;" target="_blank">view plain</a><span data-mod="popu_168">
<a href="#" class="CopyToClipboard" title="copy" onclick="dp.sh.Toolbar.Command('CopyToClipboard',this);return false;" target="_blank">copy</a><div style="position: absolute; left: 465px; top: 2326px; width: 18px; height: 18px; z-index: 99;"><embed id="ZeroClipboardMovie_5"
src="http://static.blog.csdn.net/scripts/ZeroClipboard/ZeroClipboard.swf" loop="false" menu="false" quality="best" bgcolor="#ffffff" name="ZeroClipboardMovie_5" allowscriptaccess="always" allowfullscreen="false" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer"
flashvars="id=5&width=18&height=18" wmode="transparent" width="18" height="18" align="middle"></div></span><span data-mod="popu_169"> <a href="#" class="PrintSource" title="print" onclick="dp.sh.Toolbar.Command('PrintSource',this);return false;" target="_blank">print</a></span><a
href="#" class="About" title="?" onclick="dp.sh.Toolbar.Command('About',this);return false;" target="_blank">?</a></div></div><ol start="1" class="dp-xml"><li class="alt"><span><span class="tag"><?</span><span class="tag-name">php</span><span>  </span></span></li><li
class=""><span>    print_r($_FILES["file"]);  </span></li><li class="alt"><span>    $<span class="attribute">name</span><span> = $_FILES["file"]["name"]; //中文可能乱码使用iconv函数  </span></span></li><li
class=""><span>    move_uploaded_file($_FILES["file"]["tmp_name"],iconv("UTF-8","gb2312",$name));  </span></li><li class="alt"><span><span class="tag">?></span><span>  </span></span></li></ol></div><pre name="code"
class="html" style="display: none;"><?php

    print_r($_FILES["file"]);

    $name = $_FILES["file"]["name"]; //中文可能乱码使用iconv函数

    move_uploaded_file($_FILES["file"]["tmp_name"],iconv("UTF-8","gb2312",$name));

?></pre><br>

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<p></p>

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</p>

   

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