前端 上传预览功能实现

function previewImage(file, prvid) { /* file：file控件 * prvid: 图片预览容器 */ var prvbox = document.getElementById(prvid);var tip = "请上传jpg/png/gif格式的图片文件!"; // 设定提示信息 var filters = { "jpeg" : "/9j/4", "gif" : "R0lGOD", "png" : "iVBORw" } var html1 = ‘<img src="../resources/imgs/selectImg.png" style="position: absolute;top: 50px;left: 130px;" />‘+ ????????‘<p class="showFileName" style="margin-top: 95px;color: #bfbfbf; text-align: center;">选择文件</p>‘;if (window.FileReader) { // html5方案var fileSize = file.files[0].sizeif(fileSize>500000){alert("请上传小于500K的文件!")return;}for (var i=0, f; f = file.files[i]; i++) { var fr = new FileReader(); fr.onload = function(e) { var src = e.target.result; if (!validateImg(src)) { alert(tip) } else { showPrvImg(src); } } fr.readAsDataURL(f); } } else { // 降级处理if ( !/\.jpg$|\.png$|\.gif$/i.test(file.value) ) { alert(tip); } else { var fileObj = file.files[0].size;console.log(fileObj);showPrvImg(file.value); } } function validateImg(data) { var pos = data.indexOf(",") + 1; for (var e in filters) { if (data.indexOf(filters[e]) === pos) { return e; } } return null; } function showPrvImg(src) { var img = document.createElement("img"); img.src = src; img.style.width = "270px"; img.style.height = "160px"; img.style.borderRadius = "10px"; //img.style.filter = ‘alpha(opacity:‘+50+‘)‘; //设置IE的透明度 //img.style.opacity = 50 / 100; //设置fierfox等透明度，注意透明度值是小数 prvbox.innerHTML = ""; prvbox.appendChild(img); var file = $("#files").val();var arr=file.split(‘\\‘);console.log(arr) ???????var fileName=arr[arr.length-1];console.log(fileName)//document.getElementsByClassName(‘showFileName‘).innerHTML=fileName; ????????//$(".showFileName").val(fileName); ???????//$(".showFileName").html(fileName);} }