Jquery determines whether radio, sellct, checkbox is selected and summarizes the methods of obtaining the selected value_jquery

jquery gets the value of radio button

Copy code The code is as follows:

$("input[name='items']:checked").val();

Another: Determine whether the radio is selected and obtain the selected value

As shown below:

Copy code The code is as follows:

function checkradio(){
var item = $(":radio:checked");
var len=item.length;
if(len>0){
alert("yes--the selected value is:" $(":radio:checked").val());
}
}

jquery radio value, checkbox value, select value, radio selection, checkbox selection, select selection, and related ones

Get the value of a group of radio selected items

Copy code The code is as follows:

var item = $('input[name=items][checked]').val();

Get the text of the selected item

Copy code The code is as follows:

var item = $("select[name=items] option[selected]").text();

The second element of the select drop-down box is the currently selected value

Copy code The code is as follows:

$('#select_id')[0].selectedIndex = 1;

The second element of the radio radio selection group is the currently selected value

Copy code The code is as follows:

$('input[name=items]').get(1).checked = true;

     
Get value:

Text box, text area: $("#txt").attr("value");
Multi-select box checkbox: $("#checkbox_id").attr("value");
Radio group: $("input[type=radio][checked]").val();
Drop-down box select: $('#sel').val();

Control form elements:

Text box, text area: $("#txt").attr("value",'');//Clear content

Copy code The code is as follows:

$("#txt").attr("value",'11');//Fill content

 
Multi-select box checkbox: $("#chk1").attr("checked",'');//Unchecked

Copy code The code is as follows:

$("#chk2").attr("checked",true);//Tick
if($("#chk1").attr('checked')==undefined) //Determine whether it has been checked

Radio selection group radio: $("input[type=radio]").attr("checked",'2');//Set the item with value=2 as the currently selected item

Drop-down box select: $("#sel").attr("value",'-sel3');//Set the item with value=-sel3 as the currently selected item

Copy code The code is as follows:

$("11112222").appendTo("#sel")//Add the option of the drop-down box
$("#sel").empty(); //Clear the drop-down box

     
I just started to get in touch with jquery, and I’m not familiar with many things

When using $("#id") to get the input element of the page, I found that $("#id").value cannot get the value

Later, with the help of the great Baidu, I finally found the cause of the problem:

$("") is a jquery object, not a dom element

value is an attribute of dom element

jquery corresponds to val

val(): Get the current value of the first matching element.

val(val): Set the value of each matching element.

So, the code should be written like this:

 
Value: val = $("#id")[0].value;
Assignment: $("#id")[0].value = "new value";
Or $("#id").val("new value");
Or this also works: val = $("#id").attr("value");

Each in jQuery is very easy to use, and it is often used to replace the for loop of javascript

For example, if there is an each in a function, if a certain condition in each is true, the function will return true or false

Copy code The code is as follows:

function methodone(){
....
$.each(array,function(){
if(condition is established){
return true;
}
});
....
}

It turned out that it was always wrong.

After searching for information, I discovered that break and continue cannot be used in each code block. To implement the functions of break and continue, other methods must be used
break----use return false;
continue --use return ture;

So when I want to use return true in each to return this function, I actually just let each continue to execute with
Even each is not interrupted, so function cannot return

Another: Determine whether the radio is selected and get the selected value

As shown below:

Copy code The code is as follows:

function checkradio(){
var item = $(":radio:checked");
var len=item.length;
if(len>0){
alert("yes--the selected value is:" $(":radio:checked").val());
}
}