Question

Why is logfunc “not defined”?

  var logfunc = function(obj) {
     return function() {
       console.log(obj)
     }
   }

  t += '<a onclick="logfunc(this)">&lt;</a>'

Answer 1

Reference to longfunc would not be accessible if it is declared outside of global scope, fiddle

I’m not advocating declaring variables directly in the global scope by omitting var but it makes a good example:

function setupStuff() {
    var logfunc = function(obj) { //defined within setupStuff scope
        /*...*/
    }
    t += '<a onclick="logfunc(this)">&lt;</a>';
}

function setupStuffDifferently() {
    logfuncB = function(obj) { //defined in the global scope
       /*...*/
    }
    t += '<a onclick="logfuncB(this)">&lt;</a>';
}

I would much rather see the function declared separately like

t += '<a onclick="logfunc(this)">&lt;</a>';

function logfunc(obj) { //this would work when assigned through `onclick`
       /*...*/
}

If the option is available to you, I’d suggest using a library like jQuery which offers more flexibility in assigning and handling click events.