项目经常会用到头像上传，那么怎么实现呢？
首先是HTML布局：
<label for="thumbnail" class="col-md-3 control-label">缩略图</label> <div class="col-md-6"> <input type="file" class="form-control" id="thumbnail" name="thumbnail"> </div>
jquery方式，IE不支持，但IE会获得绝对的上传路径信息：
function getObjectURL(file) {
var url = null ;
if (window.createObjectURL!=undefined) { // basic
url = window.createObjectURL(file) ;
} else if (window.URL!=undefined) { // mozilla(firefox)
url = window.URL.createObjectURL(file) ;
} else if (window.webkitURL!=undefined) { // webkit or chrome
url = window.webkitURL.createObjectURL(file) ;
}
return url ;
}
$('#thumbnail').change(function() {
var eImg = $('<img />');
eImg.attr('src', getObjectURL($(this)[0].files[0])); // 或 this.files[0] this->input
$(this).after(eImg);});
网上找一份可用的代码非常不易，经过不断的筛选总结才得出兼容所有的文件上传显示
HTML布局
<form action='' method='post' name='myform'> <input type='file' id='iptfileupload' onchange='show()' value='' /> <img src='1.jpg' alt='' id='img' /> </form>
JS代码：
<script type="text/javascript">
function getPath(obj,fileQuery,transImg) {
var imgSrc = '', imgArr = [], strSrc = '' ;
if(window.navigator.userAgent.indexOf("MSIE")>=1){ // IE浏览器判断
if(obj.select){
obj.select();
var path=document.selection.createRange().text;
alert(path) ;
obj.removeAttribute("src");
imgSrc = fileQuery.value ;
imgArr = imgSrc.split('.') ;
strSrc = imgArr[imgArr.length - 1].toLowerCase() ;
if(strSrc.localeCompare('jpg') === 0 || strSrc.localeCompare('jpeg') === 0 || strSrc.localeCompare('gif') === 0 || strSrc.localeCompare('png') === 0){
obj.setAttribute("src",transImg);
obj.style.filter=
"progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+path+"', sizingMethod='scale');"; // IE通过滤镜的方式实现图片显示
}else{
//try{
throw new Error('File type Error! please image file upload..');
//}catch(e){
// alert('name: ' + e.name + 'message: ' + e.message) ;
//}
}
}else{
// alert(fileQuery.value) ;
imgSrc = fileQuery.value ;
imgArr = imgSrc.split('.') ;
strSrc = imgArr[imgArr.length - 1].toLowerCase() ;
if(strSrc.localeCompare('jpg') === 0 || strSrc.localeCompare('jpeg') === 0 || strSrc.localeCompare('gif') === 0 || strSrc.localeCompare('png') === 0){
obj.src = fileQuery.value ;
}else{
//try{
throw new Error('File type Error! please image file upload..') ;
//}catch(e){
// alert('name: ' + e.name + 'message: ' + e.message) ;
//}
}
}
} else{
var file =fileQuery.files[0];
var reader = new FileReader();
reader.onload = function(e){
imgSrc = fileQuery.value ;
imgArr = imgSrc.split('.') ;
strSrc = imgArr[imgArr.length - 1].toLowerCase() ;
if(strSrc.localeCompare('jpg') === 0 || strSrc.localeCompare('jpeg') === 0 || strSrc.localeCompare('gif') === 0 || strSrc.localeCompare('png') === 0){
obj.setAttribute("src", e.target.result) ;
}else{
//try{
throw new Error('File type Error! please image file upload..') ;
//}catch(e){
// alert('name: ' + e.name + 'message: ' + e.message) ;
//}
}
// alert(e.target.result);
}
reader.readAsDataURL(file);
}
}
function show(){
//以下即为完整客户端路径
var file_img=document.getElementById("img"),
iptfileupload = document.getElementById('iptfileupload') ;
getPath(file_img,iptfileupload,file_img) ;
}
</script>
希望本文所述对大家学习javascript程序设计有所帮助。