Add warning about setting shorthand style prop to empty string in ie<=8

Fixes jquery#55

Author: kswedberg

entries/css.xml

@@ -69,7 +69,7 @@ div { width:60px; height:60px; margin:5px; float:left; }
     <longdesc>
       <p>As with the <code>.prop()</code> method, the <code>.css()</code> method makes setting properties of elements quick and easy. This method can take either a property name and value as separate parameters, or a single map of key-value pairs (JavaScript object notation).</p>
       <p>Also, jQuery can equally interpret the CSS and DOM formatting of multiple-word properties. For example, jQuery understands and returns the correct value for both <code>.css({'background-color': '#ffe', 'border-left': '5px solid #ccc'})</code> and <code>.css({backgroundColor: '#ffe', borderLeft: '5px solid #ccc'})</code>. Notice that with the DOM notation, quotation marks around the property names are optional, but with CSS notation they're required due to the hyphen in the name.</p>
-      <p>When using <code>.css()</code> as a setter, jQuery modifies the element's <code>style</code> property. For example,  <code>$('#mydiv').css('color', 'green')</code> is equivalent to <code>document.getElementById('mydiv').style.color = 'green'</code>. Setting the value of a style property to an empty string &#x2014; e.g. <code>$('#mydiv').css('color', '')</code> &#x2014; removes that property from an element if it has already been directly applied, whether in the HTML style attribute, through jQuery's <code>.css()</code> method, or through direct DOM manipulation of the <code>style</code> property. It does not, however, remove a style that has been applied with a CSS rule in a stylesheet or <code>&lt;style&gt;</code> element.</p>
+      <p>When using <code>.css()</code> as a setter, jQuery modifies the element's <code>style</code> property. For example,  <code>$('#mydiv').css('color', 'green')</code> is equivalent to <code>document.getElementById('mydiv').style.color = 'green'</code>. Setting the value of a style property to an empty string &#x2014; e.g. <code>$('#mydiv').css('color', '')</code> &#x2014; removes that property from an element if it has already been directly applied, whether in the HTML style attribute, through jQuery's <code>.css()</code> method, or through direct DOM manipulation of the <code>style</code> property. It does not, however, remove a style that has been applied with a CSS rule in a stylesheet or <code>&lt;style&gt;</code> element. <strong>Warning:</strong> one notable exception is that, for IE 8 and below, removing a shorthand property such as <code>border</code> or <code>background></code> will remove that style entirely from the element, regardless of what is set in a stylesheet or <code>&lt;style&gt;</code> element.</p>
       <p>As of jQuery 1.6, <code>.css()</code> accepts relative values similar to <code>.animate()</code>. Relative values are a string starting with <code>+=</code> or <code>-=</code> to increment or decrement the current value. For example, if an element's padding-left was 10px, <code>.css( "padding-left", "+=15" )</code> would result in a total padding-left of 25px.</p>
       <p>As of jQuery 1.4, <code>.css()</code> allows us to pass a function as the property value:</p>
       <pre><code>$('div.example').css('width', function(index) {
@@ -181,4 +181,4 @@ div { width:60px; height:60px; margin:5px; float:left; }
     <category slug="version/1.0"/>
     <category slug="version/1.4"/>
   </entry>
-</entries>
+</entries>