Error Eval to create control resizable

<div class='windows'>

<div style="width:400px;" class="draggable ui-widget-content">

<p class="ui-widget-header">Primeira janela</p>

<p class="ui-widget-content" id="r0">conteudo</p>

</div>

<div style="width:400px;" class="draggable ui-widget-content">

<p class="ui-widget-header">Segunda janela</p>

<p class="ui-widget-content" id="r1">conteudo</p>

</div>

</div>

<script>

$().ready(function(){

var _tdiv = $('.windows div').length; // return 2div Ok.

for(w=0;w<_tdiv;w++){

var _div = $(".windows div:eq("+w+")");

var _opt = { alsoResize:"#r"+w,minHeight:150,minWidth:200,maxHeight:500,maxWidth:920 }

_div.resizable(_opt);

}

});