<form action="">

    <img id="viewImg" src="photos.png" alt="">

    <input type="file" id="file">

</form>

        #file{

            position: absolute;

            width:;

            height:;

            visibility: hidden;

        }

        #viewImg{

            position:absolute;

            width:200px;

            height:200px;

            border-radius: 100%;

            top:50%;

            left:50%;

            margin-top: -100px;

            margin-left: -100px;

        }

var view = document.getElementById('viewImg');

        var file = document.getElementById('file');

        $(file).on('change',function(){

            var fileval = this.value;

            if(!/\.(jpg|gif|jpeg|png|bmp)$/ig.test(fileval)){

                alert("图片类型必须是.gif,jpeg,jpg,png,bmp中的一种");

                return false;

            }else{

                var url = window.URL.createObjectURL(file.files[0]);

                view.src = url;

            }

        })

        $(view).on('click',function(){

            $(file).trigger("click");

        })

function setImagePreview() {

var docObj = document.getElementById("ctl00_ContentMain_file_head");

var fileName = docObj.value;

if (!fileName.match(/.jpg|.gif|.png|.bmp/i)) {

alert('您上传的图片格式不正确，请重新选择！');

return false;

} 

var imgObjPreview = document.getElementById("preview");

if (docObj.files && docObj.files[0]) {

//火狐下，直接设img属性

imgObjPreview.style.display = 'block';

imgObjPreview.style.width = '63px';

imgObjPreview.style.height = '63px';

//imgObjPreview.src = docObj.files[0].getAsDataURL();

if (window.navigator.userAgent.indexOf("Chrome") >= 1 || window.navigator.userAgent.indexOf("Safari") >= 1) {

imgObjPreview.src = window.webkitURL.createObjectURL(docObj.files[0]);

}

else {

imgObjPreview.src = window.URL.createObjectURL(docObj.files[0]);

}

} else {

//IE下，使用滤镜

docObj.select();

docObj.blur();

var imgSrc = document.selection.createRange().text;

var localImagId = document.getElementById("localImag");

//必须设置初始大小

localImagId.style.width = "63px";

localImagId.style.height = "63px";

//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;

}