html - Function Return Behavior in Javascript -

i have <a href='...'>link</a> want invoke custom warning if click , either select "ok" or "cancel" button underlying in html taking appropriate action. default action if "ok" or nothing if "cancel."

the code in html code is:

<div id="dialogoverlay"></div> <div id="dialogbox"> <div>     <div id="dialogboxhead"></div>     <div id="dialogboxbody"></div>     <div id="dialogboxfoot"></div> </div> </div>  <a href='sumcodehere' return onclick=\"javascript: return warn.render(\'this operation cannot reversed.\')\"><img></a> 

the javascript code follows:

<script> function warn() {      this.render = function(dialog) {      var winw = window.innerwidth;       var winh = window.innerheight;       var dialogoverlay = document.getelementbyid('dialogoverlay');       var dialogbox = document.getelementbyid('dialogbox');       dialogoverlay.style.display = "block";       dialogoverlay.style.height = winh+"px";       dialogbox.style.left = (winw/2) - (550 * .5)+"px";       dialogbox.style.top = "300px";       dialogbox.style.display = "block";       document.getelementbyid('dialogboxhead').style.background = "url('../images/warninghead.gif') no-repeat";     document.getelementbyid('dialogboxhead').style.height = "30px";             document.getelementbyid('dialogboxbody').style.background = "#fbfab9";      document.getelementbyid('dialogboxbody').innerhtml = dialog;              document.getelementbyid('dialogboxfoot').style.background = "#fbfab9";      document.getelementbyid('dialogboxfoot').innerhtml = '<button onclick="return      warn.ok(); return false">go ahead , delete</button>&nbsp;<button onclick="return warn.cancel(); return true">get me out of here!</button>';              return false; } this.ok = function() {      document.getelementbyid('dialogbox').style.display = "none";      document.getelementbyid('dialogoverlay').style.display = "none";              return true; }  this.cancel = function() {      document.getelementbyid('dialogbox').style.display = "none";      document.getelementbyid('dialogoverlay').style.display = "none";              return false; }    

i'm trying in firefox, , behavior being exhibited either button brings warning dialog, both buttons, when clicked, seem returning "false."

at first html needs fixed:

<a href="sumcodehere" onclick="return warn.render('this operation cannot reversed.')">     <img src="..." alt="..." /> </a> 

(removed unknown return attribute , fixed quoting of onclick attribute.)

then in js, warn() looks constructor function, use such, , create global object:

var warn = new warn(); 

notice small letter @ beginning of variable name. same variable used in inline handler.

a better way attach event listeners elements use addeventlistener method, though.