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PHP 上传单张图片  纯 前端界面预览

上传单张图片 预览

<!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> 
<meta http-equiv="Content-Type" content="text/html; 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 = http://www.mamicode.com/evt.target.result;}"‘;
file.select();
var src = http://www.mamicode.com/document.selection.createRange().text;"<div id=divhead style=‘width:"+rect.width+"px;height:"+rect.height+"px;margin-top:"+rect.top+"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" width=100 height=100 border=0 src=http://www.mamicode.com/‘/images/defaul.jpg‘>"file" onchange="previewImage(this)" /> 
</body> 
</html>

  

图片预览方法2

<html>
<body>
<div id="test-image-preview" 
style="border: 1px solid rgb(204, 204, 204); width: 100%; height: 200px; background-size: contain; background-repeat: no-repeat; background-position: center center;"> </div>
<br/>
<div id="test-file-info"></div>
<br/>
<input type="file" id="test-image-file">
<script type="text/javascript">

var
    fileInput = document.getElementById(‘test-image-file‘),
    info = document.getElementById(‘test-file-info‘),
    preview = document.getElementById(‘test-image-preview‘);
// 监听change事件:
fileInput.addEventListener(‘change‘, function () {
    // 清除背景图片:
    preview.style.backgroundImage = ‘‘;
    // 检查文件是否选择:
    if (!fileInput.value) {
        info.innerHTML = ‘没有选择文件‘;
        return;
    }
    // 获取File引用:
    var file = fileInput.files[0];
    // 获取File信息:
    info.innerHTML = ‘文件: ‘ + file.name + ‘<br>‘ +
                     ‘大小: ‘ + file.size + ‘<br>‘ +
                     ‘修改: ‘ + file.lastModifiedDate;
    if (file.type !== ‘image/jpeg‘ && file.type !== ‘image/png‘ && file.type !== ‘image/gif‘) {
        alert(‘不是有效的图片文件!‘);
        return;
    }
    // 读取文件:
    var reader = new FileReader();
    reader.onload = function(e) {
        var
            data = e.target.result; // ‘data:image/jpeg;base64,/9j/4AAQSk...(base64编码)...‘            
        preview.style.backgroundImage = ‘url(‘ + data + ‘)‘;
    };
    // 以DataURL的形式读取文件:
    reader.readAsDataURL(file);
});
</script>

</body>
</html>

  

  

 

PHP 上传单张图片  纯 前端界面预览