基于jquery实现的上传图片及图片大小验证、图片预览效果代码_jquery

*/
function submit_upload_picture(){
var file = $('file_c').value;
if(!/.(gif|jpg|jpeg|png|gif|jpg|png)$/.test(file)){
alert("图片类型必须是.gif,jpeg,jpg,png中的一种")
}else{
$('both_form').action="file!upload.action";
$('both_form').submit();
$('insert_img').sethtml('');
$('display_div').setstyle('display', 'block');
$('upload_div').setstyle('display', 'none');
}
}

//实例二
function validate_edit_logo(a){
var file = $('file').value;
if(!/.(gif|jpg|jpeg|png|gif|jpg|png)$/.test(file)){
alert("图片类型必须是.gif,jpeg,jpg,png中的一种")
if(a==1){
return false;
}
}else{
var image = new image();
image.src = file;
var height = image.height;
var width = image.width;
var filesize = image.filesize;
$('beforeend').src=file;
$('div_regi_right').setstyle('display', 'block');
if(width>80 && height>80 && filesize>102400){
alert('请上传80*80像素 或者大小小于100k的图片');
if(a==1){
return false;
}
}
if(a==1){
return true;
}
}
}

//实例三
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 = "";
}
if (index >=3){
var cnt = index + 1;
$("img" + cnt).style.display = "";
}
}