上传图片实时预览缩略图

<script language=JavaScript>


var flag=false;




function DrawImage(ImgD)

{


var image=new Image();


image.src=develop//develop/ImgD.src;




if(image.width>0 && image.height>0)

{


flag=true;




if(image.width/image.height>= 120/80)

{




if(image.width>120)

{


ImgD.width=120;


ImgD.height=(image.height*120)/image.width;




}else

{


ImgD.width=image.width;


ImgD.height=image.height;


}


ImgD.alt=image.width+"×"+image.height;


}




else

{




if(image.height>80)

{


ImgD.height=80;


ImgD.width=(image.width*80)/image.height;




}else

{


ImgD.width=image.width;


ImgD.height=image.height;


}


ImgD.alt=image.width+"×"+image.height;


}


}




/**//**//**//*else{


ImgD.src="";


ImgD.alt=""


}*/


}






function FileChange(Value)

{


flag=false;


document.all.uploadimage.width=10;


document.all.uploadimage.height=10;


document.all.uploadimage.alt="";


document.all.uploadimage.src=/develop/Value;


}






function BeforeUpLoad()

{


if(flag) alert("OK");else alert("FAIL");


}


</script>


<INPUT style="WIDTH: 143px; HEIGHT: 18px" type=file size=8 name=pic onchange="javascript:FileChange(this.value);">


<IMG id=uploadimage height=10 width=10 src="" onload="javascript:DrawImage(this);" ><BR>


<Button onclick="javascript:BeforeUpLoad();">提交</Button>
将以上代码保存为HTM文件，即可查看运行效果