JS - 解决跨域问题

var A = document.createElement("script") , B = document.getElementsByTagName("head")[0];
A.src = "http://comment.sports.163.com/data/sports_nba_bbs/df/5C472DDM00051CA1_1.html";
A.language = "javascript";
A.type = "text/javascript";
A.onload = A.onreadystatechange = function(){
        alert(this.readyState); //onreadystatechange
        alert("A");
}

FF:onload IE:onreadystatechange

var A = document.createElement("img") , B = document.getElementsByTagName("body")[0];
A.src = "http://img.openv.tv/t/UserFiles/Image/20090612/20090612_1709056640541058.jpg";    
A.onload = A.onreadystatechange = function(){
          alert(this.readyState);
          alert("A");
}
B.appendChild(A);