function getPath()
{
//判断浏览器
var Sys = {};
var obj = document.getElementById("headImg");
var viewer = document.getElementById("viewImg");
var ua = navigator.userAgent.toLowerCase();
var s;
(s = ua.match(/msie ([d.]+)/)) ? Sys.ie = s[1] :
(s = ua.match(/firefox/([d.]+)/)) ? Sys.firefox = s[1] :
(s = ua.match(/chrome/([d.]+)/)) ? Sys.chrome = s[1] :
(s = ua.match(/opera.([d.]+)/)) ? Sys.opera = s[1] :
(s = ua.match(/version/([d.]+).*safari/)) ? Sys.safari = s[1] : 0;
var path="";
if(Sys.ie<="6.0"){
//ie5.5,ie6.0
viewer.src = obj.value;
}else if(Sys.ie>="7.0"){
//ie7,ie8
obj.select();
//加上这一句防止报告安全问题
obj.blur();
viewer.src = document.selection.createRange().text;
}else if(Sys.firefox){
if (obj.files) {
var accept = ["image/png","image/jpeg","image/jpg","image/gif"];
if (accept.indexOf(obj.files[0].type) > -1) {
var reader = new FileReader();
reader.readAsDataURL(obj.files[0]);
//延迟一会等待文件读取完毕
var t = setTimeout(function(){
viewer.src = reader.result;
clearTimeout(t);
},100)
}
}
else
{
viewer.src = obj.value;
}
}else if(Sys.chrome){
viewer.src = obj.value;
}
}
<form>
<input type="file" id="headImg" />
<input id="btnOk" type="button" value="ok" onclick="getPath()"/>
<img src="http://blog.163.com/zhchf_52@yeah/blog/" alt="view" id="viewImg" />
</form>
由于IE9不能实时的显示图片，所以采用滤镜的方法：
<style type="text/css">
#viewImg2{ /* 该对象用于在IE下显示预览图片 */
filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale);
150px;
height:150px;
display:none;
overflow: hidden;
}
#viewImg{ /* 该对象只用来在IE下获得图片的原始尺寸，无其它用途 */
filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=image);
150px;
height:150px;
display:none;
overflow:hidden;
}
</style>
<form id="uploadForm" action="" method="post" enctype="multipart/form-data">
<input type="file" id="headImg" onchange="view()" name="headImg"/>
<input type="submit" value="保存" id="btnSave" disabled="disabled" />
<p class="lineH30 color6">建议使用正方形的图片，支持JPG、GIF、PNG格式，100K以内。</p>
<div id="viewImg2"></div>
<img src="http://blog.163.com/zhchf_52@yeah/blog/" alt="" id="viewImg"/>
<script type="text/javascript">
//file文件控件，viewer 图像查看，accept支持的文件格式的mimetype数组
function viewImage(file, viewer, viewer2, btn, accept) {
//判断浏览器
var Sys = {};
if (file && viewer) {
if (!viewer2) {
viewer2 = viewer;
}
if (!accept || accept.length == 0) {
accept = ["image/png", "image/jpeg", "image/jpg", "image/gif", "image/bmp"];
}
var ua = navigator.userAgent.toLowerCase();
var s;
(s = ua.match(/msie ([d.]+)/)) ? Sys.ie = s[1] :
(s = ua.match(/firefox/([d.]+)/)) ? Sys.firefox = s[1] :
(s = ua.match(/chrome/([d.]+)/)) ? Sys.chrome = s[1] :
(s = ua.match(/opera.([d.]+)/)) ? Sys.opera = s[1] :
(s = ua.match(/version/([d.]+).*safari/)) ? Sys.safari = s[1] : 0;
var path = "";
if (Sys.ie) {
viewer.style.display = "none";
if (Sys.ie <= "6.0") {
//ie5.5,ie6.0
path = file.value;
}
else if (Sys.ie >= "7.0") {
//ie7,ie8
file.select();
//加上这一句防止报告安全问题
file.blur();
path = document.selection.createRange().text;
}
v = isValidImage(path, accept);
if (v) {
viewer2.style.display = "block";
if (viewer2.filters) {
viewer2.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = path;
}
else {
viewer2.src = path;
}
}
}
else if (Sys.firefox) {
viewer2.style.display = "none";
viewer.style.display = "block";
if (file.files && file.files.length > 0) {
if (accept.indexOf(file.files[0].type) > -1) {
var reader = new FileReader();
reader.readAsDataURL(file.files[0]);
//延迟一会等待文件读取完毕
var t = setTimeout(function () {
viewer.src = reader.result;
clearTimeout(t);
}, 100);
v = true;
}
}
else {
path = file.value;
v = isValidImage(path, accept);
if (v) {
viewer.src = file.value;
}
}
}
else {
viewer2.style.display = "none";
viewer.style.display = "block";
path = file.value;
v = isValidImage(path, accept);
if (v) {
viewer.src = file.value;
}
}
if (v) {
if (btn) {
$("#" + btn).removeAttr("disabled");
}
}
else {
viewer.src="http://blog.163.com/zhchf_52@yeah/blog/";
$("#btnSave").attr("disabled", "disabled");
}
}
}
//是否为有效的图片格式
function isValidImage(path, accept) {
var v = false;
if (path
&& path.length > 0
&& path.indexOf(".") > 0
&& accept
&& accept.length > 0) {
var idx = path.lastIndexOf(".") + 1;
if (path.length > idx) {
var ext = path.substr(idx).toLowerCase();
for (var i = 0; i < accept.length; i++) {
if (accept[i].indexOf("/" + ext) > 0) {
v = true;
break;
}
}
}
}
return v;
}
function autoSizePreview(objPre, originalWidth, originalHeight) {
var zoomParam = clacImgZoomParam(150, 150, originalWidth, originalHeight);
objPre.style.width = zoomParam.width + 'px';
objPre.style.height = zoomParam.height + 'px';
objPre.style.marginTop = zoomParam.top + 'px';
objPre.style.marginLeft = zoomParam.left + 'px';
}
function clacImgZoomParam(maxWidth, maxHeight, width, height) {
var param = { width, height: height, top: 0, left: 0 };
if (width > maxWidth || height > maxHeight) {
rateWidth = width / maxWidth;
rateHeight = height / maxHeight;
if (rateWidth > rateHeight) {
param.width = maxWidth;
param.height = height / rateWidth;
} else {
param.width = width / rateHeight;
param.height = maxHeight;
}
}
param.left = (maxWidth - param.width) / 2;
param.top = (maxHeight - param.height) / 2;
return param;
}
function view() {
viewImage(document.getElementById("headImg"),
document.getElementById("viewImg"),
document.getElementById("viewImg2"),
"btnSave",
accept);
}
</script>
</form>