实现上传头像预览

转载博客：https://blog.csdn.net/nvxiaq/article/details/77740516

<tr id="inputCB1" style="display: none">
                    <td><label> 横版图片 </label></td>
                    <td><input multiple style="300px" id="fileputHB" name="fileputHB" class="easyui-filebox" data-options='onChange:change_photo'></td>
                </tr>
                <tr id="inputCB4" style="display: none">
                    <td><label>图片预览</label></td>
                    <td> <div id="Imgdiv"><img id="Img" width="200px" height="200px"/></div></td>
                </tr>

function change_photo(){
        PreviewImage($("input[name='fileputHB']")[0], 'Img', 'Imgdiv');
    }

function PreviewImage(fileObj,imgPreviewId,divPreviewId){  
        var allowExtention=".jpg,.bmp,.gif,.png";//允许上传文件的后缀名document.getElementById("hfAllowPicSuffix").value;  
        var extention=fileObj.value.substring(fileObj.value.lastIndexOf(".")+1).toLowerCase();              
        var browserVersion= window.navigator.userAgent.toUpperCase();  
        if(allowExtention.indexOf(extention)>-1){   
            if(fileObj.files){//HTML5实现预览，兼容chrome、火狐7+等  
                if(window.FileReader){  
                    var reader = new FileReader();   
                    reader.onload = function(e){  
                        document.getElementById(imgPreviewId).setAttribute("src",e.target.result);  
                    }    
                    reader.readAsDataURL(fileObj.files[0]);  
                }else if(browserVersion.indexOf("SAFARI")>-1){  
                    alert("不支持Safari6.0以下浏览器的图片预览!");  
                }  
            }else if (browserVersion.indexOf("MSIE")>-1){  
                if(browserVersion.indexOf("MSIE 6")>-1){//ie6  
                    document.getElementById(imgPreviewId).setAttribute("src",fileObj.value);  
                }else{//ie[7-9]  
                    fileObj.select();  
                    if(browserVersion.indexOf("MSIE 9")>-1)  
                        fileObj.blur();//不加上document.selection.createRange().text在ie9会拒绝访问  
                    var newPreview =document.getElementById(divPreviewId+"New");  
                    if(newPreview==null){  
                        newPreview =document.createElement("div");  
                        newPreview.setAttribute("id",divPreviewId+"New");  
                        newPreview.style.width = document.getElementById(imgPreviewId).width+"px";  
                        newPreview.style.height = document.getElementById(imgPreviewId).height+"px";  
                        newPreview.style.border="solid 1px #d2e2e2";  
                    }  
                    newPreview.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale',src='" + document.selection.createRange().text + "')";                              
                    var tempDivPreview=document.getElementById(divPreviewId);  
                    tempDivPreview.parentNode.insertBefore(newPreview,tempDivPreview);  
                    tempDivPreview.style.display="none";                      
                }  
            }else if(browserVersion.indexOf("FIREFOX")>-1){//firefox  
                var firefoxVersion= parseFloat(browserVersion.toLowerCase().match(/firefox/([d.]+)/)[1]);  
                if(firefoxVersion<7){//firefox7以下版本  
                    document.getElementById(imgPreviewId).setAttribute("src",fileObj.files[0].getAsDataURL());  
                }else{//firefox7.0+                      
                    document.getElementById(imgPreviewId).setAttribute("src",window.URL.createObjectURL(fileObj.files[0]));  
                }  
            }else{  
                document.getElementById(imgPreviewId).setAttribute("src",fileObj.value);  
            }           
        }else{  
            alert("仅支持"+allowExtention+"为后缀名的文件!");  
            fileObj.value="";//清空选中文件  
            if(browserVersion.indexOf("MSIE")>-1){                          
                fileObj.select();  
                document.selection.clear();  
            }                  
            fileObj.outerHTML=fileObj.outerHTML;  
        }  
    }