jquery text,radio,checkbox,select operation implementation code_jquery

Control form elements:

Text box, text area:
$("#txt").attr("value") or $("#txt").val()//Get the value
$("#txt").attr("value",'');//Clear the content
$("#txt").attr("value",'11');//Fill the content

Multiple selection box checkbox:
$("#checkbox_id").attr("value") or $("#checkbox_id").val();//Get the value
$( "#chk1").attr("checked",'');//Unchecked
$("#chk2").attr("checked",true);//Checked
if( $("#chk1").attr('checked')) //Determine whether the

radio group radio has been checked:
$("input[type=radio][checked]") .val();//Get the value
$("input[name=tt]").attr("checked",'value2');//Set the item with value='value2' as the currently selected item
$("input[name=items]").get(1).checked = true;//The second element is the currently selected value

drop-down box select:
$("select [name=topSearch] option[selected]").val();//Get the value
$("select[name=topSearch] option[selected]").text();//Get the display content
$("#sel").attr("value",'sel3');//Set the item with value='sel3' as the currently selected item
$("1111 2222").appendTo("#sel")//Add the option of the drop-down box
$("#sel").empty();//Clear the drop-down box
$('#select_id' )[0].selectedIndex = 1;//The second element of the drop-down box is the currently selected value