选择国家/地区时更改颜色(change color when a country selected)

我想在<select>选项上<select>国家/地区时更改电话字段的颜色。

例如，如果有人选择英国，则颜色必须更改为红色。

但我不确定我做错了什么。 目前这不会改变。

jQuery('select[name="address[_item1][country_id]"]').change(function() {
  if (jQuery(this).val() == 'GB') {
    jQuery('#_item1telephone').css("background-color", "yellow");
  })
}); 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<select class=" required-entry countries required-entry select" name="address[_item1][country_id]" id="_item1country_id">
  <option value=""></option>
  <option value="GB">Uruguay</option>
</select>
<input type="text" class=" required-entry input-text required-entry" value="" name="address[_item1][telephone]" id="_item1telephone"> 
  
 
I am trying to change color of a telephone field when a country is selected on the <select> options.
 
For example if someone selects UK the color must change to Red.
 
But I'm not sure what I'm doing wrong. This doesn't change at the moment.
 
 
 
  
  
jQuery('select[name="address[_item1][country_id]"]').change(function() {
  if (jQuery(this).val() == 'GB') {
    jQuery('#_item1telephone').css("background-color", "yellow");
  })
}); 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<select class=" required-entry countries required-entry select" name="address[_item1][country_id]" id="_item1country_id">
  <option value=""></option>
  <option value="GB">Uruguay</option>
</select>
<input type="text" class=" required-entry input-text required-entry" value="" name="address[_item1][telephone]" id="_item1telephone"> 
  
 

                
最满意答案
                
                    
                        
 在IF声明之后你有一个无用的parens。 这段代码工作正常： 
 
jQuery('select[name="address[_item1][country_id]"]').change(function() {
  if (jQuery(this).val() == 'GB') {
    jQuery('#_item1telephone').css("background-color", "yellow");
  } // <== here
});
 
 jsFiddle演示 
You had an extraneous parens after the IF statement. This code works fine:
 
jQuery('select[name="address[_item1][country_id]"]').change(function() {
  if (jQuery(this).val() == 'GB') {
    jQuery('#_item1telephone').css("background-color", "yellow");
  } // <== here
});
 
jsFiddle Demo