<!DOCTYPE HTML>
<html>
<head>
<title>上传图片</title>
<meta charset="utf-8">
</head>
<body>
<iframe name="uploadfrm" id="uploadfrm" style="display: none;"></iframe>
<form name="formHead" method="post" action="" id="formHead" enctype="multipart/form-data" target="uploadfrm">
<div>
<div>
<input type="file" name="file_head" id="file_head" onchange="javascript:setImagePreview();" />
</div>
<div>
<div id="DivUp" style="display: none">
<input type="submit" data-inline="true" id="BtnUp" value="确认上传" data-mini="true" />
</div>
</div>
</div>
</form>
<div data-role="fieldcontain">
<div id="localImag">
<img id="preview" width="-1" height="-1" style="display: none" />
</div>
</div>
<script type="text/javascript">
function setImagePreview() {
var preview, img_txt, localImag, file_head = document.getElementById("file_head"),
picture = file_head.value;
if (!picture.match(/.jpg|.gif|.png|.bmp/i)) return alert("您上传的图片格式不正确，请重新选择！"),
!1;
if (preview = document.getElementById("preview"), file_head.files && file_head.files[0]) preview.style.display = "block",
preview.style.width = "63px",
preview.style.height = "63px",
preview.src = window.navigator.userAgent.indexOf("Chrome") >= 1 || window.navigator.userAgent.indexOf("Safari") >= 1 ? window.webkitURL.createObjectURL(file_head.files[0]) : window.URL.createObjectURL(file_head.files[0]);
else {
file_head.select(),
file_head.blur(),
img_txt = document.selection.createRange().text,
localImag = document.getElementById("localImag"),
localImag.style.width = "63px",
localImag.style.height = "63px";
try {
localImag.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)",
localImag.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = img_txt
} catch(f) {
return alert("您上传的图片格式不正确，请重新选择！"),
!1
}
preview.style.display = "none",
document.selection.empty()
}
return document.getElementById("DivUp").style.display = "block",
!0
}
</script>
</body>
</html>
来源 ::https://www.cnblogs.com/lijuntao/p/6527135.html