js本地图片预览

浏览数：37 / 时间：2015年06月09日

<!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" >
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<head>
<title>本地图片预览</title>
<style type="text/css">
#preview{width:100px;height:100px;border:1px solid #000;overflow:hidden;}
#imghead {filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=image);}
</style>

</head>
<body>
<div id="preview">
    <img id="imghead" width="100" height="100" border="0" src=‘../images/demo.jpg‘><!--无

预览时的默认图像，自己弄一个-->
</div>
<div id=‘preview1‘>
  <img id="imghead1" width="100" height="100" border="0" src=‘../images/demo.jpg‘>
</div>
    <br/>
    <br/>
    <input type="file" id=‘up‘ />



<script type="text/javascript">
function previewImage(file,oImg)
{
  var oImg1=document.getElementById(oImg);
  var MAXWIDTH  = 100;
  var MAXHEIGHT = 100;
  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]);
    
    var timer=setTimeout(function(){
      console.log(img.src);
      oImg1.src=img.src;
      
    },1000);
  }
  else
  {

    var sFilter=‘filter:progid:DXImageTransform.Microsoft.AlphaImageLoader

(sizingMethod=scale,src="‘;
    file.select();
    //var src = document.selection.createRange().text;、
    var src = this.ownerDocument.selection.CreateRange().text
    console.log(src);
    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);

    //console.log(sFilter+‘<br>‘+src+‘<br>‘+img+"<br>"+rect);
    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;margin-left:"+rect.left+"px;"+sFilter+src+"\"‘></div>";

    var timer=setTimeout(function(){
      oImg1.src=src;
    },1000);
  }


}
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;
}

window.onload=function()
{
  var oUp = document.getElementById(‘up‘);
  //var imghead1 = document.getElementById(‘imghead1‘);
  oUp.onchange=function()
  {
    previewImage(this,‘imghead1‘);
  }
}
</script>
</body>
</html>