Estoy utilizando una versión ligeramente extendida de spin.js para hermosos hilanderos y superposiciones moda spinner. Puede ser utilizado en cualquier elemento simplemente:
$('#ELEMENT_ID').spin()
o para hiladores modales:
$('#ELEMENT_ID').spin("modal")
llamada de vuelta de nuevo para desactivar y eliminar el spinner de nuevo. Esta es la forma en que parece: 
Este es el spin.min.js incluyendo una extensión de jQuery y algunos opta por defecto para hiladores modales:
//fgnass.github.com/spin.js#v1.2.6
!function(e,t,n){function o(e,n){var r=t.createElement(e||"div"),i;for(i in n)r[i]=n[i];return r}function u(e){for(var t=1,n=arguments.length;t<n;t++)e.appendChild(arguments[t]);return e}function f(e,t,n,r){var o=["opacity",t,~~(e*100),n,r].join("-"),u=.01+n/r*100,f=Math.max(1-(1-e)/t*(100-u),e),l=s.substring(0,s.indexOf("Animation")).toLowerCase(),c=l&&"-"+l+"-"||"";return i[o]||(a.insertRule("@"+c+"keyframes "+o+"{"+"0%{opacity:"+f+"}"+u+"%{opacity:"+e+"}"+(u+.01)+"%{opacity:1}"+(u+t)%100+"%{opacity:"+e+"}"+"100%{opacity:"+f+"}"+"}",a.cssRules.length),i[o]=1),o}function l(e,t){var i=e.style,s,o;if(i[t]!==n)return t;t=t.charAt(0).toUpperCase()+t.slice(1);for(o=0;o<r.length;o++){s=r[o]+t;if(i[s]!==n)return s}}function c(e,t){for(var n in t)e.style[l(e,n)||n]=t[n];return e}function h(e){for(var t=1;t<arguments.length;t++){var r=arguments[t];for(var i in r)e[i]===n&&(e[i]=r[i])}return e}function p(e){var t={x:e.offsetLeft,y:e.offsetTop};while(e=e.offsetParent)t.x+=e.offsetLeft,t.y+=e.offsetTop;return t}var r=["webkit","Moz","ms","O"],i={},s,a=function(){var e=o("style",{type:"text/css"});return u(t.getElementsByTagName("head")[0],e),e.sheet||e.styleSheet}(),d={lines:12,length:7,width:5,radius:10,rotate:0,corners:1,color:"#000",speed:1,trail:100,opacity:.25,fps:20,zIndex:2e9,className:"spinner",top:"auto",left:"auto"},v=function m(e){if(!this.spin)return new m(e);this.opts=h(e||{},m.defaults,d)};v.defaults={},h(v.prototype,{spin:function(e){this.stop();var t=this,n=t.opts,r=t.el=c(o(0,{className:n.className}),{position:"relative",width:0,zIndex:n.zIndex}),i=n.radius+n.length+n.width,u,a;e&&(e.insertBefore(r,e.firstChild||null),a=p(e),u=p(r),c(r,{left:(n.left=="auto"?a.x-u.x+(e.offsetWidth>>1):parseInt(n.left,10)+i)+"px",top:(n.top=="auto"?a.y-u.y+(e.offsetHeight>>1):parseInt(n.top,10)+i)+"px"})),r.setAttribute("aria-role","progressbar"),t.lines(r,t.opts);if(!s){var f=0,l=n.fps,h=l/n.speed,d=(1-n.opacity)/(h*n.trail/100),v=h/n.lines;(function m(){f++;for(var e=n.lines;e;e--){var i=Math.max(1-(f+e*v)%h*d,n.opacity);t.opacity(r,n.lines-e,i,n)}t.timeout=t.el&&setTimeout(m,~~(1e3/l))})()}return t},stop:function(){var e=this.el;return e&&(clearTimeout(this.timeout),e.parentNode&&e.parentNode.removeChild(e),this.el=n),this},lines:function(e,t){function i(e,r){return c(o(),{position:"absolute",width:t.length+t.width+"px",height:t.width+"px",background:e,boxShadow:r,transformOrigin:"left",transform:"rotate("+~~(360/t.lines*n+t.rotate)+"deg) translate("+t.radius+"px"+",0)",borderRadius:(t.corners*t.width>>1)+"px"})}var n=0,r;for(;n<t.lines;n++)r=c(o(),{position:"absolute",top:1+~(t.width/2)+"px",transform:t.hwaccel?"translate3d(0,0,0)":"",opacity:t.opacity,animation:s&&f(t.opacity,t.trail,n,t.lines)+" "+1/t.speed+"s linear infinite"}),t.shadow&&u(r,c(i("#000","0 0 4px #000"),{top:"2px"})),u(e,u(r,i(t.color,"0 0 1px rgba(0,0,0,.1)")));return e},opacity:function(e,t,n){t<e.childNodes.length&&(e.childNodes[t].style.opacity=n)}}),function(){function e(e,t){return o("<"+e+' xmlns="urn:schemas-microsoft.com:vml" class="spin-vml">',t)}var t=c(o("group"),{behavior:"url(#default#VML)"});!l(t,"transform")&&t.adj?(a.addRule(".spin-vml","behavior:url(#default#VML)"),v.prototype.lines=function(t,n){function s(){return c(e("group",{coordsize:i+" "+i,coordorigin:-r+" "+ -r}),{width:i,height:i})}function l(t,i,o){u(a,u(c(s(),{rotation:360/n.lines*t+"deg",left:~~i}),u(c(e("roundrect",{arcsize:n.corners}),{width:r,height:n.width,left:n.radius,top:-n.width>>1,filter:o}),e("fill",{color:n.color,opacity:n.opacity}),e("stroke",{opacity:0}))))}var r=n.length+n.width,i=2*r,o=-(n.width+n.length)*2+"px",a=c(s(),{position:"absolute",top:o,left:o}),f;if(n.shadow)for(f=1;f<=n.lines;f++)l(f,-2,"progid:DXImageTransform.Microsoft.Blur(pixelradius=2,makeshadow=1,shadowopacity=.3)");for(f=1;f<=n.lines;f++)l(f);return u(t,a)},v.prototype.opacity=function(e,t,n,r){var i=e.firstChild;r=r.shadow&&r.lines||0,i&&t+r<i.childNodes.length&&(i=i.childNodes[t+r],i=i&&i.firstChild,i=i&&i.firstChild,i&&(i.opacity=n))}):s=l(t,"animation")}(),typeof define=="function"&&define.amd?define(function(){return v}):e.Spinner=v}(window,document);
var default_opts = {
lines: 9,
length: 2,
width: 3,
radius: 8,
corners: 1,
rotate: 0,
color: '#555',
speed: 1,
trail: 47,
shadow: false,
hwaccel: false,
className: 'spinner',
zIndex: 2e9,
top: 'auto',
left: 'auto'
};
var modal_opts = {
lines: 11, // The number of lines to draw
length: 23, // The length of each line
width: 8, // The line thickness
radius: 40, // The radius of the inner circle
corners: 1, // Corner roundness (0..1)
rotate: 9, // The rotation offset
color: '#FFF', // #rgb or #rrggbb
speed: 1, // Rounds per second
trail: 50, // Afterglow percentage
shadow: true, // Whether to render a shadow
hwaccel: false, // Whether to use hardware acceleration
className: 'spinner', // The CSS class to assign to the spinner
zIndex: 2e9, // The z-index (defaults to 2000000000)
top: 'auto', // Top position relative to parent in px
left: 'auto' // Left position relative to parent in px
};
//jQuery extension
$.fn.spin = function(opts) {
if (opts == null) opts = default_opts;
if (opts == "modal") opts = modal_opts;
this.each(function() {
var $this = $(this),
data = $this.data();
if (data.spinner) {
data.spinner.stop();
delete data.spinner;
if (opts == modal_opts) $("#spin_modal_overlay").remove();
return this;
}
var spinElem = this;
if (opts == modal_opts){
$('body').append('<div id="spin_modal_overlay" style="background-color: rgba(0, 0, 0, 0.6); width:100%; height:100%; position:fixed; top:0px; left:0px; z-index:'+(opts.zIndex-1)+'"/>');
spinElem = $("#spin_modal_overlay")[0];
}
data.spinner = new Spinner($.extend({color: $this.css('color')}, opts)).spin(spinElem);
});
return this;
};
Gracias por la sugerencia, pero por desgracia eso no es todo lo que estoy buscando Necesito tener la visualización de la animación de carga luego de que se hayan dibujado las funciones simplemodal-overlay y simplemodal-container, pero antes de que se muestre el contenido de mi iframe. – messedupfir
¿$ .modal tiene una opción de devolución de llamada? –