【JavascriptDemo】无刷新预览所选择的图片

javascript文章/教程1年前 (2023)发布勤奋小助

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1.效果如下，可测试

2.代码如下

<!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>无标题文档</title>
<script type="text/javascript">
    //本地图片预览
            function setImagePreview(fieldupload, image, imagediv) {
                var docObj = document.getElementById(fieldupload);
                var imgObjPreview = document.getElementById(image);
                if (docObj.files && docObj.files[0]) {
                    //火狐下，直接设img属性                        
                    imgObjPreview.style.display = 'block';
                    imgObjPreview.style.width = '150px';
                    imgObjPreview.style.height = '150px';
                    //imgObjPreview.src = docObj.files[0].getAsDataURL();      
                    //火狐7以上版本不能用上面的getAsDataURL()方式获取，需要一下方式        
                    imgObjPreview.src = window.URL.createObjectURL(docObj.files[0]);
                } else {
                    //IE下，使用滤镜                        
                    docObj.select();
                    var imgSrc = document.selection.createRange().text;
                    var localImagId = document.getElementById(imagediv);
                    //必须设置初始大小                        
                    localImagId.style.width = "150px";
                    localImagId.style.height = "150px";
                    //图片异常的捕捉，防止用户修改后缀来伪造图片
                    try {
                        localImagId.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)"; localImagId.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = imgSrc;
                    } catch (e) {
                        alert("您上传的图片格式不正确，请重新选择!");
                        return false;
                    }
                    imgObjPreview.style.display = 'none';
                    document.selection.empty();
                }
                return true;
            }
</script>
</head>

<body>
<div id="localImag"> <img id="preview" width="150px" height="150px"  src="http://images.cnblogs.com/likecs_com/yc-755909659/559257/o_%e6%9a%82%e6%97%a0%e5%9b%be%e7%89%87.gif" alt="" /></div>
<div>
  <input type="file" onchange="javascript:setImagePreview('upload','preview','localImag');" id="upload" />
</div>
</body>
</html>