上传图片

<!DOCTYPE HTML>
<html>
<head>
    <title>上传图片</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
</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>
原文地址:https://www.cnblogs.com/lichunjing/p/7066300.html