Returning the Name of a column header [closed]

Answer 1

Try this

var td     = document.getElementsByTagName("td"),
    titles = document.getElementsByTagName("th");

for ( var i = 0; i < td.length; i++ ) {   
    td[i].addEventListener("click", function() {
        alert( titles[this.cellIndex].innerHTML );
    }, false);
}

DEMO

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UPDATE

If the click should happen on the table head only

var titles = document.getElementsByTagName("th");

for ( var i = 0, len = titles.length; i < len; i++ ) {   
    titles[i].addEventListener("click", function() {
        alert( this.innerHTML );
    }, false);
}

DEMO