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Thread: Javascript function returns NaN

  1. #1
    Junior Member
    Join Date
    Feb 2011
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    Default Javascript function returns NaN

    sorry folks if this post is not pertaining to jsp. I could'nt find a forum for javascript in here. so I am posting it here.

    I've a jsp with a <html:text> element which is supposed to accept year values only.
    I've added an onblur js function to check if it is the correct entry.

    My Js function is as follows:
    <script type="text/javascript" >
    function isYear(yrval)
    	if (yrval==null || yrval=="" || yrval=="0")
    		alert("Invalid value in Year!!");
    		return false;
    	var nyr=Number(yrval);
    	var curdt = new Date();
    	var cy = curdt.getFullYear();
    	if (nyr>cy)
    		alert("Calendar Year cannot be greater than "+cy);
    		return false;
    	if (nyr)<(cy-1))
    		alert("You cannot enter data prior to year "+cy-1);
    		return false;
    	return true;
    now my jsp looks as follows:
    HTML Code:
    <div id="content">
    <html:form action="/Savedata">
    <table id="mytbl" >
    	<tr><td class="tbhr" colspan="2">YEAR</td></tr>
    	<tr><td>Select Year:</td><td><html:text name="myvo" property="calYear" size="5" maxlength="4" onkeypress="return onlyNumbers();" onblur="return isYear(this.value);"/></td></tr>
    Now the problem : The alerts in js function is showing as NaN. Even for
    valid inputs, it's displaying the same message.

    Am i missing something here?

  2. #2
    Junior Member
    Join Date
    Apr 2011
    Thanked 1 Time in 1 Post

    Default Re: Javascript function returns NaN

    The value you are passing to isyear function is not a number.

  3. #3
    Super Moderator Json's Avatar
    Join Date
    Jul 2009
    Warrington, United Kingdom
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    Thanked 156 Times in 152 Posts

    Default Re: Javascript function returns NaN

    You might need to do something like this.

    var cy = new Number(curdt.getFullYear());

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