jQuery: set value for element from JSON-object

Question

This may be hard to explain, but I have array object like this:

myobject = {
  "class1"     : "value1",
  "class2"     : "value2",
  "class3"     : "value3",
  ...
}

and I have script

$.each(myobject,function(i,val){
try{
    var it=0;
    $("." + i).each(function(it){
        switch($("." + i)[it].nodeName){
            case "SPAN":case "A":case "DIV":
                $("." + i).html(val);
            break;
            case "INPUT":
                switch($("." + i).attr("type")){
                    case "submit":
                        $("." + i).attr("value",val);
                    break;
                    case "text":case "password":case "email":
                        $("." + i).attr("placeholder",val);
                    break;
                }
            break;
            case "IMG":
                $("." + i).attr("alt",val);
                $("." + i).attr("title",val);
            break;
        }
    });
}catch(err){
    // Nothing
}
});

Effect of code for span , a , div should be this:

Was:  <span class="class1"></span>
Is:   <span class="class1">value1</span>

and for input where type=submit , it should be this:

Was:  <input type="submit" class="class2" />
Is:   <input type="submit" class="class2" value="value2" />

Code effects for span , a , div and input[type=submit] , but this won't set placeholder s. Why?

Answer 1

What you're trying is an overly complicated way to do what you want. Just use the power of the jQuery selector to your advantage to filter by tag type:

$.each(myobject, function(k, v){
    $('span.' + k + ', ' +
      'a.' + k + ', ' +
      'div.' + k).html(v);

    $('input.' + k + '[type="submit"]').val(v);

    $('input.' + k + '[type="text"], ' +
      'input.' + k + '[type="password"], ' +
      'input.' + k + '[type="email"]').attr('placeholder', v);

    $('img.' + k).attr('title', v)
                 .attr('alt', v);
});

EDIT:

See demo

(perhaps you can figure out from looking between the demo and your code what's different and why it's not working)