jsp上传图片实时显示

jsp代码

<div class="form-group" id="caseIma">
<label class="control-label">案例图片</label>
<label class="btn btn-primary">选择图片
<input type="file" style="display: none" class="form-control" id="caseImage" name="caseImage"
onchange="viewImage(this)"/>
</label>
!--<p class="help-block">建议尺寸88*88</p>-->
</div>
<div id="localImag"><img id="preview" width=-1 height=-1 style="diplay:none" />
</div>

js代码

//上传图片后预览图片
function viewImage(file){
            var preview = document.getElementById('preview');
            if(file.files && file.files[0]){
                //火狐下
                preview.style.display = "block";
                preview.style.width = "300px";
                preview.style.height = "120px";
                preview.src = window.URL.createObjectURL(file.files[0]);
            }else{
                //ie下，使用滤镜
                file.select();
                var imgSrc = document.selection.createRange().text;
                var localImagId = document.getElementById("localImag");
                //必须设置初始大小
                localImagId.style.width = "250px";
                localImagId.style.height = "200px";
                try{
                localImagId.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)";
                locem("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;
                }
                preview.style.display = 'none';
                document.selection.empty();
                }
                return true;
        }