您的位置：首页 > Web前端 > JavaScript

js 图片上传本地预览

2015-06-10 11:43 597 查看

<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>图片上传本地预览</title>
<style type="text/css">
#preview{width:260px;height:190px;border:1px solid #000;overflow:hidden;}
#imghead {filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=image);}
</style>
<script type="text/javascript">
//图片上传预览    IE是用了滤镜。
function previewImage(file) {
var MAXWIDTH  = 260;
var MAXHEIGHT = 180;
var div = document.getElementById('preview');
if (file.files && file.files[0]) {
div.innerHTML ='<img id=imghead>';
var img = document.getElementById('imghead');
img.onload = function(){
var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight);
img.width  =  rect.width;
img.height =  rect.height;
// img.style.marginLeft = rect.left+'px';
// img.style.marginTop = rect.top+'px';
}
var reader = new FileReader();
reader.onload = function(evt){img.src = evt.target.result;}
reader.readAsDataURL(file.files[0]);
} else {
//兼容IE
var sFilter='filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale,src="';
file.select();
var src = document.selection.createRange().text;
div.innerHTML = '<img id=imghead>';
var img = document.getElementById('imghead');
img.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src = src;
var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight);
status =('rect:'+rect.top+','+rect.left+','+rect.width+','+rect.height);
// div.innerHTML = "<div id=divhead style='width:"+rect.width+"px;height:"+rect.height+"px;margin-top:"+rect.top+"px;"+sFilter+src+"\"'></div>";
div.innerHTML = "<div id=divhead style='width:"+rect.width+"px;height:"+rect.height+"px;"+sFilter+src+"\"'></div>";
}
}

function clacImgZoomParam( maxWidth, maxHeight, width, height ){
var param = {top:0, left:0, width:width, height:height};
if ( width>maxWidth || height>maxHeight ) {
rateWidth = width / maxWidth;
rateHeight = height / maxHeight;

if( rateWidth > rateHeight ) {
param.width =  maxWidth;
param.height = Math.round(height / rateWidth);
} else {
param.width = Math.round(width / rateHeight);
param.height = maxHeight;
}
}

param.left = Math.round((maxWidth - param.width) / 2);
param.top = Math.round((maxHeight - param.height) / 2);
return param;
}
</script>
</head>
<body>

<div id="preview">
<img id="imghead" border="0" src="head_180.jpg" width="180" height="180" />
</div>
<input type="file" onchange="previewImage(this)" />

</body>
</html>

内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理

标签：

相关文章推荐

新的分享

章节导航