if($toWH<=$srcWH){$ftoW=$toW;$ftoH=$ftoW*($srcH/$srcW)}else{$ftoH=$toH$ftoW=$ftoH*($srcW/$srcH)}

function ImageShow(maxWidth,maxHeight,objImg){var img=new Image();img.src=objImg.src;var w=img.width;var h=img.height;if(w==maxWidth&&h==maxHeight){objImg.width=maxWidth;objImg.height=maxHeight;return};var b1=w/h;var b2=maxWidth/maxHeight;if(b1>b2){objImg.height=maxHeight;objImg.width=maxHeight/h*w;objImg.style.marginLeft=-(maxHeight*w-maxWidth*h)/(2*h)+'px'}else{objImg.widt=maxWidth;objImg.height=maxWidth/w*h;objImg.style.margnTop=-(maxWidth*h-maxHeight*w)/(2*w)+'px'};return};