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Detailed example of JS implementation of uploading images and previewing them
Detailed example of JS implementation of uploading images and previewing them
This article mainly introduces the real-time preview function of uploaded images using JS. It is very good and has reference value. Friends who need it can refer to the code that I found on the Internet some time ago and modified part of it. in the project. The original blog address cannot be found. If the original author sees it, leave a message and it will be deleted as soon as possible.
//js本地图片预览，兼容ie[6-9]、火狐、Chrome17+、Opera11+、Maxthon3
function PreviewImage(fileObj) {
//创建dom元素
var pPreviewId = 'pPreview_' + fileObj.name;
var imgPreviewId = 'imgHeadPhoto_' + fileObj.name;
var html='<p id="'+pPreviewId+'">'+
'<img id="'+imgPreviewId+'" src="images/moren.jpg" style="width: 120px; height: 120px; border: solid 1px #d2e2e2;" />'+
'</p>';
$('#'+pPreviewId).remove();
$(fileObj).after(html);
//进行限制
var allowExtention = ".jpg,.bmp,.gif,.png"; //允许上传文件的后缀名document.getElementById("hfAllowPicSuffix").value;
var extention = fileObj.value.substring(fileObj.value.lastIndexOf(".") + 1).toLowerCase();
var browserVersion = window.navigator.userAgent.toUpperCase();
if (allowExtention.indexOf(extention) > -1) { //格式正确
if (fileObj.files) { //HTML5实现预览，兼容chrome、火狐7+等
if (window.FileReader) {
var reader = new FileReader();
reader.onload = function (e) {
document.getElementById(imgPreviewId).setAttribute("src", e.target.result);
}
reader.readAsDataURL(fileObj.files[0]);
} else if (browserVersion.indexOf("SAFARI") > -1) {
$('#'+pPreviewId).remove();
alert("不支持Safari6.0以下浏览器的图片预览!");
}
} else if (browserVersion.indexOf("MSIE") > -1) {
if (browserVersion.indexOf("MSIE 6") > -1) {//ie6
document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
} else {//ie[7-9]
fileObj.select();
if (browserVersion.indexOf("MSIE 9") > -1)
fileObj.blur(); //不加上document.selection.createRange().text在ie9会拒绝访问
var newPreview = document.getElementById(pPreviewId + "New");
if (newPreview == null) {
newPreview = document.createElement("p");
newPreview.setAttribute("id", pPreviewId + "New");
newPreview.style.width = document.getElementById(imgPreviewId).width + "px";
newPreview.style.height = document.getElementById(imgPreviewId).height + "px";
newPreview.style.border = "solid 1px #d2e2e2";
}
newPreview.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale',src='" + document.selection.createRange().text + "')";
var temppPreview = document.getElementById(pPreviewId);
temppPreview.parentNode.insertBefore(newPreview, temppPreview);
temppPreview.style.display = "none";
}
} else if (browserVersion.indexOf("FIREFOX") > -1) {//firefox
var firefoxVersion = parseFloat(browserVersion.toLowerCase().match(/firefox\/([\d.]+)/)[1]);
if (firefoxVersion < 7) {//firefox7以下版本
document.getElementById(imgPreviewId).setAttribute("src", fileObj.files[0].getAsDataURL());
} else {//firefox7.0+
document.getElementById(imgPreviewId).setAttribute("src", window.URL.createObjectURL(fileObj.files[0]));
}
} else {
document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
}
} else {
$('#'+pPreviewId).remove();
alert("仅支持" + allowExtention + "为后缀名的文件!");
fileObj.value = ""; //清空选中文件
if (browserVersion.indexOf("MSIE") > -1) {
fileObj.select();
document.selection.clear();
}
fileObj.outerHTML = fileObj.outerHTML;
}
return fileObj.value; //返回路径
}【Related recommendations】
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