检查元素是否存在导致浏览器中的脚本错误

Question

仅当页面上存在包含某些文本的元素时，我才尝试将 Qtip 插件附加到元素。由于某种原因，我不断收到脚本错误，提示“AddTooltips() 不是函数”。在元素不存在的页面上。我的 if 语句不太适用。

$(document).ready(function() {

 function AddTooltips() {
  var infoIcon = '<img class="actionItem catInfo" style="margin-left:4px" src="/images/00_Core/info.gif"/>';
  var $Age = $("div.question h3:contains('Age')");
  var $Gender = $("div.question h3:contains('Gender')");
  var $Questions = $("div.question h3:contains('Age'), div.question h3:contains('Gender')");
  $Questions.append(infoIcon);
  $.fn.qtip.styles.speStyle = { // Last part is the name of the style
   width: 400,
   border: {
    width: 2,
    radius: 6
   },
   name: 'light' // Inherit the rest of the attributes from the preset dark style
  };
  $Age.children("img.catInfo").qtip({content: 'Some Copy.', style: 'speStyle'
  });
  $Gender.children("img.catInfo").qtip({content: 'Some Different Copy.', style: 'speStyle'
  });
 }


 if ( $("div.question h3:contains('Age')").length > 0 || $("div.question h3:contains('Gender')").length > 0 ) {  
  AddTooltips();
 }
});

Answer 1

将 AddTooltips() 放在 dom 就绪事件之外，如下所示：

function AddTooltips() {
    var infoIcon = '<img class="actionItem catInfo" style="margin-left:4px" src="/images/00_Core/info.gif"/>',
        $Age = $("div.question h3:contains('Age')"),
        $Gender = $("div.question h3:contains('Gender')"),
        $Questions = $("div.question h3:contains('Age'), div.question h3:contains('Gender')");

    $Questions.append(infoIcon);
    $.fn.qtip.styles.speStyle = { // Last part is the name of the style
        width: 400,
        border: {
            width: 2,
            radius: 6
        },
        name: 'light' // Inherit the rest of the attributes from the preset dark style
    };
    $Age.children("img.catInfo").qtip({content: 'Some Copy.', style: 'speStyle'});
    $Gender.children("img.catInfo").qtip({content: 'Some Different Copy.', style: 'speStyle'});
}

$(function() {
    if ($("div.question h3:contains('Age'), div.question h3:contains('Gender')").length) {  
        AddTooltips();
    }
});