让图片自动适应大小

function imgadapter(obj,width,height){var max_height = height; //设置最大高度var max_width = width; //设置最大宽度var real_height = obj.height;var real_width = obj.width;if(obj.height>max_height){obj.height = max_height;obj.width = Math.round(obj.height*real_width/real_height);}if(obj.width>max_width){obj.width = max_width;obj.height = Math.round(obj.width*real_height/real_width);}}