关于js中this所指代元素的问题
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <script type="text/javascript" src="jquery-1.8.1.js"></script><script type="text/javascript">var flag=false;function DrawImage(ImgD,imageWidth,imageHeight) { var image=new Image(); image.src=ImgD.src; console.log(image.src);//输出“file:///D:/WebStorm%20WorkSpace/test5/undefined” if(image.width>0 && image.height>0){ flag=true; if(image.width/image.height>= imageWidth/imageHeight){ if(image.width>imageWidth){ ImgD.width=imageWidth; ImgD.height=(image.height*imageWidth)/image.width; }else{ ImgD.width=image.width; ImgD.height=image.height; } } else{ if(image.height>imageHeight){ ImgD.height=imageHeight; ImgD.width=(image.width*imageHeight)/image.height; }else{ ImgD.width=image.width; ImgD.height=image.height; } } } } $("#pic").ready(function(){ DrawImage(this,150,130);//图片大小没有改变,为什么? }) </script><title>Anddecor</title></head><body><img alt="" src="img/ipad.jpg" id="pic"/>/*定义图片宽不超过150,高不超过130*/</body></html>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><script type="text/javascript">var flag=false;function DrawImage(ImgD,imageWidth,imageHeight) { var image=new Image(); image.src=ImgD.src; if(image.width>0 && image.height>0){ flag=true; if(image.width/image.height>= imageWidth/imageHeight){ if(image.width>imageWidth){ ImgD.width=imageWidth; ImgD.height=(image.height*imageWidth)/image.width; }else{ ImgD.width=image.width; ImgD.height=image.height; } } else{ if(image.height>imageHeight){ ImgD.height=imageHeight; ImgD.width=(image.width*imageHeight)/image.height; }else{ ImgD.width=image.width; ImgD.height=image.height; } } } } </script><title>Anddecor</title></head><body><img alt="" src="img/ipad.jpg" onload= "javascript:DrawImage(this,150,130)" />/*定义图片宽不超过150,高不超过130*/</body></html>
window.onload=function(){ var img=document.getElementById("pic"); DrawImage(img,150,130);}