struts的一个小问题

Question

用struts标签时,在表单检测的时候不能定位光标 怎么办 ?document.forms["taxPayerBasicInfo"].["taxPayerBasicInfo.dexm"].focus();
这句代码报错

Answer 1

document.forms["taxPayerBasicInfo"].elements["taxPayerBasicInfo.dexm"].focus();

Answer 2

document.getElementById("dexm").focus();

Answer 3

document.getElementById("num"+id).className='err';
document.getElementById("num"+id).focus();
document.getElementById("num"+id).select();

Answer 4

document.getElementById("num"+id).focus();