Hello
Try to js as following way
<script language="javascript" type="text/javascript" src="jQuery.js"></script>
<script language="javascript" type="text/javascript">
$(document).ready(function() {
$('#btnClick').click(function() {
$("#div1").toggle(2000, function() {
$("#div2").width(5); //Changing width 'n' to 98%
$("#div2").css("float", "left");
});
});
});
</script>
<asp:Button ID="btnClick" runat="server" OnClientClick="javascript:void(0);return false;"
Text="Button" />
<div style="float: left" id="div1">
TEst1
</div>
<div style="float: left" id="div2">
TEst2 TEst2 TEst2 TEst2 TEst2 TEst2 TEst2
</div>
Pls check it and let me know your feedback.