//jquery实现图片预览的方法实例
function viewimg(index) {
var name = 'uploadimg' + index;
var imgup = $(name);
var imgpath = getpath(imgup);
var local = imgup.value;
var point = local.lastindexof(".");
//判断上传文件大小
var img = document.createelement("img");
img.src = local;
var filesize = img.filesize;
img.onload = function(){filesize=this.filesize;}
if(img.filesize>5242880){
alert("图片文件过大！");
return false;
}
//判断是否是图片格式
var imgname = imgup.value.substring(imgup.value.lastindexof("."), imgup.value.length);
imgname = imgname.tolowercase();
if ((imgname != ".jpg") && (imgname != ".gif") && (imgname != ".jpeg") && (imgname != ".png") && (imgname != ".bmp")) {
alert("u8bf7u9009u62e9u56feu7247u6587u4ef6uff0cu8c22u8c22!");
imgup.focus();
//清空file里面的值www.3ppt.com
imgup.select();
document.selection.clear();
} else {
//显示图片
document.getelementbyid("sig_preview"+index).innerhtml = "<img src='" + imgpath + "' border=0 width=200 height=150><img src='images/u51.png' width='16' height='14' onclick='delimage(" + index + ");' />";
}
if (index >=3){
var cnt = index + 1;
$("img" + cnt).style.display = "";
}
}