Why doesn't my “IF” statement work? (Works if commented out)
Question
So I'm new to jQuery, and I can't figure out why my IF statement isn't working, although code works when I comment out the IF. Please help me...Thanks!
<html>
<head>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.7.1.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("tr.anon").hide();
$("#hideID").change(function(){
// IF ($("#hideID option[value='no']").text()){
$("tr.anon").show();
// alert($this).find("option:selected").text()+' clicked!');
// }ELSE{
// $("tr.anon").hide();
// }
});
});
</script>
</head>
<body>
<p>Would you like to remain anonymous? <select id="hideID">
<option value="yes">Yes</option>
<option value="no">No</option>
</select></p>
<table border="1px">
<tr class="anon">
<td>Enter your name:</td>
<td><input class="field2" type="text" /></td>
</tr>
</table>
</body>
</html>
Thanks for the quick feedback... I have adjusted my code to the following but it still is not working.
<html>
<head>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.7.1.min.js"></script><script type="text/javascript">
$(document).ready(function(){
$("tr.anon").hide();
$("#hideID").change(function(){
// if ($("#hideID option[value='no']").text()){
$("tr.anon").show();
// alert(#hideID).find("option:selected").text()+' clicked!');
// }else{
// $("tr.anon").hide();
// }
});
});
</script>
</head>
<body>
<p>Would you like to remain anonymous?
<select id="hideID">
<option value="yes">Yes</option>
<option value="no">No</option>
</select></p>
<table border="1px">
<tr class="anon">
<td>Enter your name:</td>
<td><input class="field2" type="text" /></td>
</tr>
</table>
</body>
</html>
7 answers
solution1
3 2011-12-06 18:14:24
你不应该使用CAPS进行IF和ELSE ！
solution2
1 2011-12-06 18:24:13
if and else must be lower-case. Javascript is case-sensitive.
Also, I don't think the if clause here is doing what you want. You are testing the truthiness of #hideID option[value='no'] , which will always evaluate to true. I think you really want to check whether the 'no' value is selected. Also, you are simply toggling visibility, so jQuery's toggle method would be more appropriate here.
Try this instead:
$('tr.anon').toggle( $("#hideID option:selected").val() === "no" );
solution3
0 2011-12-06 18:14:34
还要确保你没有在大写字母中写下'if ... else'语句！
solution4
0 2011-12-06 18:14:53
Javascript is case sensitive, your if and else should be lowercase.
Also, you're checking whether $("#hideID option[value='no']").text() is truthy or not. If the text is anything other than an empty string you will go down the true path, is this your intention?
solution5
0 2011-12-06 18:44:27
Ok, let's try this... I fixed the script to work. You can see the changes.
<script type="text/javascript">
$(document).ready(function(){
$("tr.anon").hide();
$("#hideID").change(function(){
if ($("#hideID").val()=="no"){
$("tr.anon").show();
alert($(this).find("option:selected").text() + ' clicked!');
} else {
$("tr.anon").hide();
$("#textFieldID").val("");
}
});
});
</script>
solution6
0 2011-12-06 18:47:01
Since you just have the two values, you can use this:
Demo: http://jsfiddle.net/ThinkingStiff/eqxCa/
Script:
$( 'tr.anon' ).hide();
$( '#hideID' ).change( function() { $( 'tr.anon' ).toggle(); } );
solution7
-2 ACCPTED 2011-12-06 18:12:07
Change to value==='no'. = is for assignment, and == and === are comparison.
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