javascript - dynamic variables

Question

Hi I am trying to make dynamic variables but it is saying `variable v0 (through to v5) is not defined.

td.each(function(i){
eval(\'var v\' + i + \' = \\\'\'          


        

Answer 1

That sounds like a bad idea.

Is there any reason you can't do this?

var tdHtml = td.map(function() { return $(this).html(); }).get();

Answer 2

Oh my.

If you want to create a global "dynamic variable" you should not use var. In this context it creates a variable that is local inside of the each-function, which is quite useless (and will cause it to be undefined outside of the loop, which is what you're experiencing). Instead you should do it like this:

td.each(function(i){
  window['v' + i] = $(this).html();
});

The downside with the above code is that global variables are not really great either.

On the other hand, if you want a local variable (if for example there will be more code in the loop that uses this varaible, then I would do it like this:

td.each(function(i){
  var dynVars = {};
  dynVars['v' + i] = $(this).html();

  alert(dynVars.v4); // use the dynamic variables by saying "dynVars.NAME"

});

You could combine these two solutions, by putting the declaration of dynvars (var dynVars = {}) in the scope where you want to be able to access your variables instead. As long as it is also visible in this each-callback, everything will work out fine.