Basic javascript help with if function

**fefefasesdfs** · March 30th, 2010, 09:36 PM

I need to make a simple program where the user inputs into a text box a number, then clicks a button and another text box returns whether the number is greater or less than 20. I know its an if function but not sure what to put. Also does this require parsefloat? Any help at all is greatly appreciated

This is all I have
<html>

<head>
<title> Compare A Number to 20 </title>
</head>
<body>
<p>Enter a number</p>
<input type="text" id="num1" value= "" size="10" />
<br/>
<input type="button" id="btn" value= "Compare With 20" onClick=" ? " />
<br/>
<input type="text" id="btn" size="10" />
</script>
</body>
</html>

**mgnstrong** · March 30th, 2010, 10:50 PM

well, first off you're missing a script starting tag

But basically what you could do is write a javascript method to handle the comparison, and call it as the button's onClick handler

your method would look something like

function doSomething () {
if (document.getElementById('num1').value < 20 ){
alert ('The value you entered was less than 20');
}
else {
alert ('The value you entered was not less than 20');
}
}

now i dont think you should have to use the parsefloat function, i think .value returns it as a number... but I could be wrong. (javascript isn't my strongest language) If it looks like I am, pop it in there.

Hope that helps?

**sandeeptheviper** · August 8th, 2010, 10:29 AM

hi
hope this will help
just copy the code and paste it in notepad and save it with .htm extension and your work is done

<HTML>
<HEAD>
<title> Compare A Number to 20 </title>
<SCRIPT LANGUAGE="JavaScript">
function doSomething () {
if (document.getElementById('num1').value < 20 ){
num2.value="less than 20"
}
else if(document.getElementById('num1').value != 20 ){
num2.value="greater than 20"
}
else
num2.value="equal to 20"
}
</SCRIPT>
</HEAD>
<BODY>

<p>Enter a number</p>
<p>
<input type="text" id="num1" value= "" size="10" />
<br/>
<p>
<input type="button" id="btn" value= "Compare With 20" onClick="javascript:doSomething()" />
<br/>
<p>
<input type="text" id="num2" size="10" />
</SCRIPT>
</BODY>
</HTML>

read the code its very easy
if you find this code confusing then sorry. post a message i will try to explain it