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[JS]实现图片上传预览

2016-11-21 15:54 609 查看

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html>

<head>

<title></title>

</head>

<body>

<div id="divPreview">

<img id="imgHeadPhoto" src="noperson.jpg" style="width: 160px; height: 170px; border: solid 1px #d2e2e2;"

alt="" />

</div>

<input type="file" onchange="PreviewImage(this,'imgHeadPhoto','divPreview');" size="20" />

<script type="text/javascript">

//js本地图片预览，兼容ie[6-9]、火狐、Chrome17+、Opera11+、Maxthon3

function PreviewImage(fileObj, imgPreviewId, divPreviewId) {

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) {

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) {

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(divPreviewId + "New");

if (newPreview == null) {

newPreview = document.createElement("div");

newPreview.setAttribute("id", divPreviewId + "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 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", 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 {

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

}

</script>

</body>

</html>

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