从Dictionary对象列表中查找值(Finding a value from within a List of Dictionary objects)

 由于此问题已更新，表明您需要2个提醒。 
 
 使用if/elseif块，块将在第一次匹配时完成。 所以在你的代码中，一旦匹配250 ，if语句就完成了，而elseif永远不会被评估。 
 
 要获得独立执行的多个条件，它们应该是多个if语句： 
 
$('#lblShowCounter').each(function () {
    var text = $(this).text(),
        matched;

    if (text >= '300') {
        alert('blink');
        matched = true;
    }
    if (text >= '250') {
        alert('red');
        matched = true;
    }

    if (!matched) {
        alert('nothing');
    }
});

Since the question has since been updated to indicate you want 2 alerts.
 
With an if/elseif block, the block will complete once it hits the first match. So in your code, once it matches 250 the if statement completes and the elseif is never evaluated.
 
To get multiple conditions to execute independently, they should be multiple if statements:
 
$('#lblShowCounter').each(function () {
    var text = $(this).text(),
        matched;

    if (text >= '300') {
        alert('blink');
        matched = true;
    }
    if (text >= '250') {
        alert('red');
        matched = true;
    }

    if (!matched) {
        alert('nothing');
    }
});