javascript - I am new to node js how to get dependent dynamic dropdown from database -


my node code:

app.get('/block_name', function (req,res){  var sql='select  `block_name`,`block_id` `tbl_block`  '; connection.query(sql,function(err, result) {     if (err) throw err;     res.json(result); });

});

app.get('/site_name', function (req,res){

var sql='select  `site_name`,`site_id` `tbl_site` '; connection.query(sql,function(err, result) {     if (err) throw err;     res.json(result); });

});

html

site

      <select name="site" id="dropdown" >         <option value="">- select -</option>       </select>      <label class="field" >block</label>       <select name="block" id="dropdown1" >         <option value="">- select -</option>       </select>

script

<script>      $(document).ready(function(){     $.ajax({         url : "/site_name",         type : "get",         success : function(data){              var len = data.length;              console.log(data);             $("#dropdown").empty();             for(var =0; i<len;i++){             var value1 = data[i]['site_name'];             var value2 = data[i]['site_id'];                 $("#dropdown").append("<option value='"+value2+"' >"+value1+"</option>");              }          }     }); });       $(document).ready(function(){     $.ajax({         url : "/block_name",         type : "get",         success : function(data){              var len = data.length;              console.log(data);             $("#dropdown1").empty();             for(var =0; i<len;i++){             var value1 = data[i]['block_name'];             var value2 = data[i]['block_id'];                 $("#dropdown1").append("<option value='"+value2+"' >"+value1+"</option>");              }          }     }); });     </script>

my second dropdown lists data need particular thing listed according first dropdown. in advance.. sorry bad english

anytime first drop-down changes value, need repopulate second drop-down based on select value in first drop-down - rerunning ajax call load second drop-down, using value of first drop-down decide data request server.

you installing event handler on first drop-down can detect time value changed , repopulate second dropdown fresh ajax call whenever event on first drop-down occurs.


Comments

Post a Comment

Popular posts from this blog

Is there a better way to structure post methods in Class Based Views -

i'm using class based views in django , never specify url in ajax calls , omit action parameter in form because know these requests go through post method of class based view. notice view - profile page make many requests depending on user updating on page - post method become convoluted , if/else mess example: def post(self, request, *args, **kwargs): # handle user changing available date if request.post.get('availabledate') != none: self.updateavailabledate(request) return jsonresponse({'result':'success'}) if request.post.get('newprojectname') != none: creative_user = creativeuserprofile.objects.get(id = request.user.id) project = project.create_project(creative_user, request.post['newprojectname']) project.save() return jsonresponse({'projectid': project.id }) if request.post.get('projectimage') != none , request.files['file']: proj
Read more

performance - Why is XCHG reg, reg a 3 micro-op instruction on modern Intel architectures? -

i'm doing micro-optimization on performance critical part of code , came across sequence of instructions (in at&t syntax): add %rax, %rbx mov %rdx, %rax mov %rbx, %rdx i thought had use case xchg allow me shave instruction , write: add %rbx, %rax xchg %rax, %rdx however, dimay found agner fog's instruction tables , xchg 3 micro-op instruction 2 cycle latency on sandy bridge, ivy bridge, broadwell, haswell , skylake. 3 whole micro-ops , 2 cycles of latency! 3 micro-ops throws off 4-1-1-1 cadence , 2 cycle latency makes worse original in best case since last 2 instructions in original might execute in parallel. now... cpu might breaking instruction micro-ops equivalent to: mov %rax, %tmp mov %rdx, %rax mov %tmp, %rdx where tmp anonymous internal register , suppose last 2 micro-ops run in parallel latency 2 cycles. given register renaming occurs on these micro-architectures, though, doesn't make sense me done way. why wouldn't register renamer
Read more

jquery - Responsive Navbar with Sub Navbar -

good day, forgive me nav vocabulary not best. if question confusing apologize. i'm working on navigation bar needs centered on page @ 768px , above. items in nav open (or perhaps toggle) subnav lives directly below. these nav should appear centered on page. i have been able work through responsive portion of nav bar, having main items align vertically , sub nav menu of each item roll out below, , gave them indent separation. working well. however, issue not responsive side, behavior @ width greater 768px. happens toggling menu's sub navigation pushes other main items down page below sub nav. here's code: $(document).ready(function () { //stick in fixed 100% height behind navbar don't wrap $('#slide-nav.navbar-inverse').after($('<div class="inverse" id="navbar-height-col"></div>')); $('#slide-nav.navbar-default').after($('<div id="navbar-height-col"></d
Read more