function addImgCaptions() {
    var imgs = document.getElementsByTagName("img");
	
	for(i = 0; i < imgs.length; i++) {
	  if(imgs[i].className.search(/\bhasCaption\b/) != -1) {
	    var p = document.createElement("p");
		p.className = "imgCaption";
		var ptxt = document.createTextNode(imgs[i].alt);
		p.appendChild(ptxt);
		imgs[i].parentNode.insertBefore(p, imgs[i].nextSibling);
	  }
	}  
  }

  function initialize() {
    addImgCaptions();
  }
  
  window.onload = initialize;