如何在javascript中使用AND语句？(How can use AND statement in if with javascript?)
大家好，我试图运行多个JavaScript并使用AND语句。 当用户点击具有值=“1986”的选项并点击其他值为“3”的选项时，将出现一些文本。 我在if语句中使用了AND语句，但它不起作用。 这是我的代码：
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js"></script></script> <script type="text/javascript"> $(document).ready(function() { $('#main').on('change', '.select-box', function() { if ($(".select-box option[value='3']").attr('selected') & $(".select-box option[value='1986']").attr('selected')) { $('#demo').html("Hello World"); } }); }); </script> <script type="text/javascript"> var x="",i; for(i=1986;i<2013;i++) { x=x + "<option value='"+i+"'> " + i + "</option>"; } $(document).ready(function() { document.getElementById("demo2").innerHTML="<select class='select-box'>"+x+"</select>"; }); </script> </head> <body> <p id="demo2"></p> <div id="main"> <select class="select-box"> <option value="0">alert</option> <option value="1">alert to</option> <option value="2">no alert</option> <option value="3">best alert</option> </select> <p><br/> <div id="demo"></div> </div> </body>Hello everyone I'm trying to run multiple javascripts and use AND statement. When user click an option which has value="1986" and click other option which has value="3", some text will appear. I have used AND statement in if statement but it doesn't work. Here is my code :
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js"></script></script> <script type="text/javascript"> $(document).ready(function() { $('#main').on('change', '.select-box', function() { if ($(".select-box option[value='3']").attr('selected') & $(".select-box option[value='1986']").attr('selected')) { $('#demo').html("Hello World"); } }); }); </script> <script type="text/javascript"> var x="",i; for(i=1986;i<2013;i++) { x=x + "<option value='"+i+"'> " + i + "</option>"; } $(document).ready(function() { document.getElementById("demo2").innerHTML="<select class='select-box'>"+x+"</select>"; }); </script> </head> <body> <p id="demo2"></p> <div id="main"> <select class="select-box"> <option value="0">alert</option> <option value="1">alert to</option> <option value="2">no alert</option> <option value="3">best alert</option> </select> <p><br/> <div id="demo"></div> </div> </body>最满意答案
要使用AND语句，它应该是&& 。
所以你的if语句应该是
if ($(".select-box option[value='3']").attr('selected') && $(".select-box option[value='1986']").attr('selected')) { $('#demo').html("Hello World"); }这里是关于布尔逻辑的更多信息。
To use the AND statement, it should be &&.
So for your if statement it should be
if ($(".select-box option[value='3']").attr('selected') && $(".select-box option[value='1986']").attr('selected')) { $('#demo').html("Hello World"); }Here is more information on boolean logic.
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