function chkSearch()
{
  var obj=document.search;
  if(!obj.keyword.value){
    alert("Please input keyword");
    obj.keyword.focus();
    return(false);
  }
}
function chkSearchAndSend(){
  var obj=document.search;
  if(obj.keyword.value==""){
    alert("Please input keyword");
    obj.keyword.focus();
    return(false);
  }else{
  	obj.fireEvent('onsubmit');
  }
}
function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}

/* tab switching */
function tab_switch (id) {
	if (id == 'interviews' || id == 'challenges' || id == 'stories') {
		document.getElementById('interviews_ft').className = (id == 'interviews') ? 'box_on' : 'box_off';	
		document.getElementById('interviews_tab').className = (id == 'interviews') ? 'tab_active_down' : '';
		
		document.getElementById('challenges_ft').className = (id == 'challenges') ? 'box_on' : 'box_off';	
		document.getElementById('challenges_tab').className = (id == 'challenges') ? 'tab_active_down' : '';

		document.getElementById('stories_ft').className = (id == 'stories') ? 'box_on' : 'box_off';	
		document.getElementById('stories_tab').className = (id == 'stories') ? 'tab_active_down' : '';
		
	}

	if (id == 'website' || id == 'design' || id == '3d' || id == 'other') {
		document.getElementById('share_website').className = (id == 'website') ? 'box_on' : 'box_off';
		document.getElementById('share_website_tab').className = (id == 'website') ? 'tab_active_up' : '';
		
		document.getElementById('share_design').className = (id == 'design') ? 'box_on' : 'box_off';
		document.getElementById('share_design_tab').className = (id == 'design') ? 'tab_active_up' : '';
		
	}
	
}

//nav_tab_change
function goto(object)
{
	if (document.getElementById(object).style.display=='none'){
		document.getElementById('homes').style.display='none';
		document.getElementById('homes1').className='nav_td_black_1';
		document.getElementById('homes2').className='nav_td_black_2';
		document.getElementById('homes3').className='nav_td_black_3';
		document.getElementById('homes4').className='td_black_4';		
		
		document.getElementById('news').style.display='none';
		document.getElementById('news1').className='nav_td_black_1';
		document.getElementById('news2').className='nav_td_black_2';
		document.getElementById('news3').className='nav_td_black_3';	
		document.getElementById('news4').className='td_black_4';					
		
		document.getElementById('gallery').style.display='none';
		document.getElementById('gallery1').className='nav_td_black_1';
		document.getElementById('gallery2').className='nav_td_black_2';
		document.getElementById('gallery3').className='nav_td_black_3';
		document.getElementById('gallery4').className='td_black_4';	
		
		document.getElementById('ui').style.display='none';
		document.getElementById('ui1').className='nav_td_black_1';
		document.getElementById('ui2').className='nav_td_black_2';
		document.getElementById('ui3').className='nav_td_black_3';
		document.getElementById('ui4').className='td_black_4';							
				
		document.getElementById('techniques').style.display='none';
		document.getElementById('techniques1').className='nav_td_black_1';
		document.getElementById('techniques2').className='nav_td_black_2';
		document.getElementById('techniques3').className='nav_td_black_3';	
		document.getElementById('techniques4').className='td_black_4';				
				
		document.getElementById('tutorials').style.display='none';
		document.getElementById('tutorials1').className='nav_td_black_1';
		document.getElementById('tutorials2').className='nav_td_black_2';
		document.getElementById('tutorials3').className='nav_td_black_3';	
		document.getElementById('tutorials4').className='td_black_4';				
				
		document.getElementById('downloads').style.display='none';
		document.getElementById('downloads1').className='nav_td_black_1';
		document.getElementById('downloads2').className='nav_td_black_2';
		document.getElementById('downloads3').className='nav_td_black_3';	
		document.getElementById('downloads4').className='td_black_4';				
		
		/*		
		document.getElementById('forums').style.display='none';	
		document.getElementById('forums1').className='nav_td_black_1';
		document.getElementById('forums2').className='nav_td_black_2';
		document.getElementById('forums3').className='nav_td_black_3';	
		document.getElementById('forums4').className='td_black_4';				
		*/
				
		document.getElementById(object).style.display='';		
		document.getElementById(object+"1").className='nav_td_blue_1';
		document.getElementById(object+"2").className='nav_td_blue_2';
		document.getElementById(object+"3").className='nav_td_blue_3';
		document.getElementById(object+"4").className='td_blue_4';	
	}
}

//图片按比例缩放
var flag_iz=false;
function DrawImage(ImgD,iwidth,iheight){
    //参数(图片,允许的宽度,允许的高度)
    var image=new Image();
    image.src=ImgD.src;
    if(image.width>0 && image.height>0){
		flag_iz=true;
		if(image.width/image.height>= iwidth/iheight){
			if(image.width>iwidth){  
				ImgD.width=iwidth;
				ImgD.height=(image.height*iwidth)/image.width;
			}else{
				ImgD.width=image.width;  
				ImgD.height=image.height;
			}
		} else{
			if(image.height>iheight){  
				ImgD.height=iheight;
				ImgD.width=(image.width*iheight)/image.height;        
			}else{
				ImgD.width=image.width;  
				ImgD.height=image.height;
			}
		}
    }
}