javascript: focus()文本框文字最后获得焦点光标,兼容多浏览器

可兼容火狐FF, IE浏览器,谷歌浏览器,其它浏览器基于IE内核应该也支持

cobj = document.getElementById("comment"); //

cobj.value='内容 '+cont+'：'; //加上内容

//cobj.focus();

cobj.focus(); //得到焦点

var len = cobj.value.length;

if(document.selection) {

    var sel = cobj.createTextRange();

    sel.moveStart('character',len);

    sel.collapse();

    sel.select();

} else if (typeof cobj.selectionStart == 'number' && typeof cobj.selectionEnd == 'number') {

    cobj.selectionStart = cobj.selectionEnd = len;

}