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HTML5 Programming Practice Part 3 - Image Text (txt) Drag and Drop Preview Implementation Code
- 黄舟Original
- 2017-03-30 13:33:281424browse
The main knowledge used in this article
HTML5File and FileReaderInterface
Source code
<!DOCTYPE html><html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title>HTML5文件拖拽预览Demo</title>
<style type="text/css">
h1{
padding:0px;
margin:0px;
}
p#show{
border: 1px solid #ccc;
width: 400px;
height: 300px;
display: -moz-box;
display: -webkit-box;
-moz-box-align: center;
-webkit-box-align: center;
-moz-box-pack: center;
-webkit-box-pack: center;
resize:both;
overflow:auto;
}
p[id^=show]:hover{
border: 1px solid #333;
}
p#main{
width:100%;
}
p#successLabel {
color:Red;
}
p#content {
display:none;
}
</style>
<script type="text/javascript">
function init()
{ var dest = document.getElementById("show");
dest.addEventListener("dragover", function(ev)
{
ev.stopPropagation();
ev.preventDefault();
}, false);
dest.addEventListener("dragend", function(ev)
{
ev.stopPropagation();
ev.preventDefault();
}, false);
dest.addEventListener("drop", function (ev) {
ev.stopPropagation();
ev.preventDefault();
var file = ev.dataTransfer.files[0];
var reader = new FileReader();
if (file.type.substr(0, 5) == "image") {
reader.onload = function (event) {
dest.style.background = 'url(' + event.target.result + ') no-repeat center';
dest.innerHTML = "";
};
reader.readAsDataURL(file);
} else if (file.type.substr(0, 4) == "text") {
reader.readAsText(file);
reader.onload = function (f) {
dest.innerHTML = "<pre class="brush:php;toolbar:false">" + this.result + "";
dest.style.background = "white";
}
} else {
dest.innerHTML = "暂不支持此类文件的预览";
dest.style.background = "white";
}
}, false);
}
//设置页面属性，不执行默认处理（拒绝被拖放）
document.ondragover = function(e){e.preventDefault();};
document.ondrop = function(e){e.preventDefault();}
window.onload=init;
HTML5文件拖拽预览Demo
文件预览区，仅限图片和txt文件