JS图片上传预览
想实现上传预览功能.
首先想到考虑再inputfile change时候上传图片到服务器.然后再返回一个图片地址加入到Dom里面。然后听小斌说用JS预览本地图片.（我X!!!还有这玩意,为啥我不知道!!!）然后真的立马爽多了.
源代码:
<html xmlns="https://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>get file input full path</title>
<script type="text/javascript">
function PreviewImage(obj, imgPreviewId, divPreviewId) {
var allowExtention = ".jpg,.bmp,.gif,.png"; //,允许上传文件的后缀名
var extention = obj.value.substring(obj.value.lastIndexOf(".") + 1).toLowerCase();
var browserVersion = window.navigator.userAgent.toUpperCase();
if (allowExtention.indexOf(extention) > -1) {
if (browserVersion.indexOf("MSIE") > -1) {
if (browserVersion.indexOf("MSIE 6.0") > -1) {//ie6
document.getElementById(imgPreviewId).setAttribute("src", obj.value);
} else {//ie[7-8]、ie9
obj.select();
var newPreview = document.getElementById(divPreviewId + "New");
if (newPreview == null) {
newPreview = document.createElement("div");
newPreview.setAttribute("id", divPreviewId + "New");
newPreview.style.width = 160;
newPreview.style.height = 170;
newPreview.style.border = "solid 1px #d2e2e2";
}
newPreview.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale',src='" + document.selection.createRange().text + "')";
var tempDivPreview = document.getElementById(divPreviewId);
tempDivPreview.parentNode.insertBefore(newPreview, tempDivPreview);
tempDivPreview.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", obj.files[0].getAsDataURL());
} else {//firefox7.0+
document.getElementById(imgPreviewId).setAttribute("src", window.URL.createObjectURL(obj.files[0]));
}
} else if (obj.files) {
//兼容chrome、火狐等，HTML5获取路径
if (typeof FileReader !== "undefined") {
var reader = new FileReader();
reader.onload = function (e) {
document.getElementById(imgPreviewId).setAttribute("src", e.target.result);
}
reader.readAsDataURL(obj.files[0]);
} else if (browserVersion.indexOf("SAFARI") > -1) {
alert("暂时不支持Safari浏览器!");
}
} else {
document.getElementById(divPreviewId).setAttribute("src", obj.value);
}
} else {
alert("仅支持" + allowSuffix + "为后缀名的文件!");
obj.value = ""; //清空选中文件
if (browserVersion.indexOf("MSIE") > -1) {
obj.select();
document.selection.clear();
}
obj.outerHTML = obj.outerHTML;
}
}
</script>
</head>
<body>
<form name="form5" id="form5">
<input type="file" name="file5" id="file5" onchange="PreviewImage(this,'imgView','divNewPreview')"/>
<img id="imgView" src="" alt="" />
<div id="divNewPreview"></div>
</form>
</body>
</html>
实际上是把上传的图片转换为了base64显示的.这种方法太方便了!