javascript - jQuery keeps posting an extra message each time I click submit -

my jquery code acting weird. keeps posting copy of same message each time click on submit. example:

hello 3 hello 3 hello 3 hello 2 hello 2 hello  

anyone have idea why happening? here code far:

jquery(function ($) {     var socket = io.connect();     var $messageform = $('#sendmessage');     var $messagetitle = $('#title');     var $messagebox = $('#message');     var $chat = $('#chat');      $messageform.click(function (e) {         if ($.trim($("#title").val()).length === 0) {             alert('you must provide valid input');             $messagetitle.val('');             $messagebox.val('');             return false;         }         if ($.trim($("#message").val()).length === 0) {             alert('you must provide valid input');             $messagetitle.val('');             $messagebox.val('');             return false;         } else {             e.preventdefault();             socket.emit('send message', '<b>' + $messagetitle.val() + '</b>' + '&nbsp;-&nbsp;' + $messagebox.val());             $messagetitle.val('');             $messagebox.val('');         }          socket.on('new message', function (data) {             $chat.prepend(data + "<br/>");         });     }); }); 

this function here registers event handler every time it's called. because you're calling in click event, every time click, register new event handler. these managed in queue, , thus, run through event handler time each button click.

socket.on('new message', function (data) {             $chat.prepend(data + "<br/>");         }); 

the solution move outside of click event.

jquery(function ($) {     var socket = io.connect();     var $messageform = $('#sendmessage');     var $messagetitle = $('#title');     var $messagebox = $('#message');     var $chat = $('#chat');      $messageform.click(function (e) {         if ($.trim($("#title").val()).length === 0) {             alert('you must provide valid input');             $messagetitle.val('');             $messagebox.val('');             return false;         }         if ($.trim($("#message").val()).length === 0) {             alert('you must provide valid input');             $messagetitle.val('');             $messagebox.val('');             return false;         } else {             e.preventdefault();             socket.emit('send message', '<b>' + $messagetitle.val() + '</b>' + '&nbsp;-&nbsp;' + $messagebox.val());             $messagetitle.val('');             $messagebox.val('');         }     });     socket.on('new message', function (data) {         $chat.prepend(data + "<br/>");     });    });