文件上传立马预览

上传一个图片之后想要立刻预览图片。直接将<input type="file">标签的路径直接赋给<img>标签的src好像不可以，写了一个方法。

<img id="image"/>

<input type="file" id="upload"/>

<script type="text/javascript">

        $("#upload").uploadPreview({ Img: "image", Width: 110, Height: 135 });

<script>

前提是要导入jquery-xxx-min.js

另外写一个js文件upload.js 将其导入，代码如下

jQuery.fn.extend({
    uploadPreview: function (opts) {
        var _self = this,
            _this = $(this);
        opts = jQuery.extend({
            Img: "img-head",
            Width: 100,
            Height: 100,
            ImgType: ["gif", "jpeg", "jpg", "bmp", "png"],
            Callback: function () {}
        }, opts || {});
        _self.getObjectURL = function (file) {
            var url = null;
            if (window.createObjectURL != undefined) {
                url = window.createObjectURL(file);
            } else if (window.URL != undefined) {
                url = window.URL.createObjectURL(file);
            } else if (window.webkitURL != undefined) {
                url = window.webkitURL.createObjectURL(file);
            }
            return url;
        };
        _this.change(function () {
            if (this.value) {
                if (!RegExp("\.(" + opts.ImgType.join("|") + ")$", "i").test(this.value.toLowerCase())) {
                    alert("选择文件错误,图片类型必须是" + opts.ImgType.join("，") + "中的一种");
                    this.value = "";
                    return false;
                }
                if ($.browser.msie) {
                    try {
                        $("#" + opts.Img).attr('src', _self.getObjectURL(this.files[0]));
                    } catch (e) {
                        var src = "";
                        var obj = $("#" + opts.Img);
                        var div = obj.parent("div")[0];
                        _self.select();
                        if (top != self) {
                            window.parent.document.body.focus();
                        } else {
                            _self.blur();
                        }
                        src = document.selection.createRange().text;
                        document.selection.empty();
                        obj.hide();
                        obj.parent("div").css({
                            'filter': 'progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)',
                            'width': opts.Width + 'px',
                            'height': opts.Height + 'px'
                        });
                        div.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = src;
                    }
                } else {
                    $("#" + opts.Img).attr('src', _self.getObjectURL(this.files[0]));
                }
                opts.Callback();
            }
        });
    }
});