js实现图片上传并正常显示

原文链接：https://www.jb51.net/article/76651.htm

js实现图片上传并正常显示

1.html代码部分

<form action='' method='post' name='myform'>
 <input type='file' id='iptfileupload' onchange='show()' value='' />
 <img src='1.jpg' alt='' id='img' />
</form>

1.javascript代码部分

<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>