一段JS验证代码，可有高人来简化下

JScript code

function toDelete(id){    var id = document.getElementById('id').value;    var orgId = document.getElementById('orgId').value;    var documentOrgId = document.getElementById('documentOrgId').value;    var parentId = document.getElementById('parentId').value;    var documentTypeList = document.getElementById('documentTypeList').value;    var documentList = document.getElementById('documentList').value;    if (id == '') {        alert("请选择目录");    }    else if (orgId == documentOrgId) {            if (parentId == '') {                alert("根目录不能删除");            } else if (documentTypeList == '[]' && documentList == '[]' ) {                         if(confirm("您真的要删除此目录吗")) {                              window.location='doDeleteDocumentType.do?documentType.id='+id;                         } else {                            return;                        }                      } else if (documentTypeList == '[]') {                           alert("目录下有资料，不能删除");                      } else if (documentList == '[]') {                            alert("目录下有子目录，不能删除");                       } else {                            alert("目录下有子目录和资料，不能删除");                         }        } else {            alert("非本公司添加，不能删除");        }}