js上传展示本地图片

请求的Js：

<script type="text/javascript">
 ???$(function () {
 ???????$(‘#<?php echo $k; ?>‘).change(function () {
 ???????????var url = getFileUrl(‘<?php echo $k; ?>‘);
 ???????????if(url == ‘‘){
 ???????????????$(‘#<?php echo $k; ?>_img‘).css(‘display‘,‘none‘);
 ???????????}else{
 ???????????????$(‘#<?php echo $k; ?>_img‘).attr(‘src‘,url).css(‘display‘,‘‘);
 ???????????????$(‘#<?php echo $k; ?>_err‘).html(‘‘);
 ???????????}
 ???????});
 ???})

function getFileUrl(sourceId) {
 ???var url;
 ???if (navigator.userAgent.indexOf("MSIE")>=1) { // IE
 ???????url = document.getElementById(sourceId).value;
 ???} else if(navigator.userAgent.indexOf("Firefox")>0) { // Firefox
 ???????url = window.URL.createObjectURL(document.getElementById(sourceId).files.item(0));
 ???} else if(navigator.userAgent.indexOf("Chrome")>0) { // Chrome
 ???????url = window.URL.createObjectURL(document.getElementById(sourceId).files.item(0));
 ???}else{
 ???????url = window.URL.createObjectURL(document.getElementById(sourceId).files.item(0));
 ???}
 ???return url;
}

</script>

<form action="/mobile/my_order_controller/do_trademark_operation" method="post" id="form" enctype="multipart/form-data" onkeydown="if(event.keyCode==13)return false;"></form>

后端处理：
通过 $_FILES 接收存储图片