从剪贴板粘贴图片

function pasteEvent(event) {
    event = event || window.event;
    var theClipboardData = event.clipboardData || window.clipboardData;
    if (theClipboardData) {
		var items = theClipboardData.items;
		for (var i = 0; i < items.length; ++i) {
			var item = theClipboardData.items[i];
			if (items[i].kind == 'file' && items[i].type == 'image/png') {
				var fileReader = new FileReader();
				fileReader.onloadend = function () {
					var d = this.result.substr( this.result.indexOf(',')+1);
					var img = document.createElement("img");
					img.src= "data:image/png;base64,"+d;
					document.body.appendChild(img);
				};
				fileReader.readAsDataURL(item.getAsFile());
				break;
			}
		}
    }
};