simple java help (homework)

**collicott** · 03-01-2009, 01:47 AM

Cant figure out why this is not working any help would be great.

function bulletf2()
{
var bulletspeed = 1325;
var bulletDistance;
var bulletTime;
var bulletDistance = document.getElementById('InID2');
bulletTime= bulletDistance/ bulletspeed;
var bulletTime = document.getElementById('OutID2');

}

//-->
</script>
</head>
<body bgcolor="#C0C000">
<H1> #2. Midterm Test Practice for <font color="blue">extra</font></H1><HR/>



<P style="color: #0000ff; border=2">a view of your javascript code...</P>
<textarea style="background-color: #ffffcc;" cols=80 rows=8>
</textarea><hr/>
<P style="color: #800080">2. A bullet travels at 1325 meter's per second.
Write a program that will input the Distance and Show the Time.</P>
<H3>bullet Input Distance <input type="text" size="20" ID="InID2" onkeyup="bulletf2()" /></H3>
<H3>bullet Output Time <input type="text" size="40" ID="OutID2" /></H3>

**Falkon303** · 03-01-2009, 02:17 AM

dude it's for a mid-term, I suggest you google the hell out of javascript.

I'll help you do this, but don't shoot yourself in the foot (pun!).

**Nile** · 03-01-2009, 02:21 AM

1) You have to select the value, not the element
2) You have to assign the elements value bulletTime, not assign bulletTime's value to the element.

There is also a much easier way to do this which I have already done... I don't know if I should give it to you considering it's homework.

**Nile** · 03-01-2009, 02:27 AM

Your code doesn't work...
You're missing a slash in it's.. should be: it\'s.
(btw: taking out the document.write, the code doesn't work.

)

**Falkon303** · 03-01-2009, 02:28 AM

Originally Posted by Nile

Your code doesn't work...
You're missing a slash in it's.. should be: it\'s.

fixed it, thanx.

**Nile** · 03-01-2009, 02:30 AM

Your code doesn't work though... Were you trying to make it work? Or help him?

**Falkon303** · 03-01-2009, 02:33 AM

Originally Posted by collicott

Cant figure out why this is not working any help would be great.

function bulletf2()
{
var bulletspeed = 1325;
var bulletDistance;
var bulletTime;
var bulletDistance = document.getElementById('InID2');
bulletTime= bulletDistance/ bulletspeed;
var bulletTime = document.getElementById('OutID2');

}

//-->
</script>
</head>
<body bgcolor="#C0C000">
<H1> #2. Midterm Test Practice for <font color="blue">extra</font></H1><HR/>



<P style="color: #0000ff; border=2">a view of your javascript code...</P>
<textarea style="background-color: #ffffcc;" cols=80 rows=8>
</textarea><hr/>
<P style="color: #800080">2. A bullet travels at 1325 meter's per second.
Write a program that will input the Distance and Show the Time.</P>
<H3>bullet Input Distance <input type="text" size="20" ID="InID2" onkeyup="bulletf2()" /></H3>
<H3>bullet Output Time <input type="text" size="40" ID="OutID2" /></H3>

here's the deal...
Let's say you have an input element right?
<input id="ninja" name="ninja" value="el">

ok, first off, if we want to replace this element's value, we use this
document.getElementById('ninja').value - "new text";

what we are doing is targetting the element based on the id="ninja" part of <input id="ninja" name="ninja" value="el"> .
what was wrong in your formula was that you were trying to divide raw string values.... first you have to wrap each value, like - parseFloat(bulletDistance) / parseFloat(the otherthing).

I think some of your values set for variables were absolutely blank as well...
Assign them like this ----
var BulletThingy = document.getElementById("whateverelement").value;

now to change the value of an element it's the other way...
document.getElementById("whateverelement").value = "7";

parseFloat("numericvalue") tells javascript that the values are to be treated as mathematical (correct me if I am wrong guys).

**Nile** · 03-01-2009, 02:35 AM

Ehh... Almost...
Here was trying to divide raw html objects... In javascript, it does:

Code:

[HtmlInputObject] / 1325

Or something like that.

(your code doesn't work!)

**Falkon303** · 03-01-2009, 02:40 AM

Originally Posted by Nile

Your code doesn't work though... Were you trying to make it work? Or help him?

I screwed it up when I was trying to be witty.... damn you pride! Foiled again!

Code:

<script type="text/javascript">
function bulletf2(value)
{
var bulletspeed = 1325;
var bulletDistance = value;
var bulletTime;
var bulletDistance = document.getElementById('InID2').value;
bulletTime= parseFloat(bulletDistance)/ parseFloat(bulletspeed);
document.getElementById('OutID2').value = bulletTime;
} 
//-->
</script>
</head>
<body bgcolor="#C0C000">
<H1> #2. Midterm Test Practice for <font color="blue">extra</font></H1><HR/>
<!-- ---------------------------------------------------------------------- -->
<!-- Copy of your java script code for show! -->
<!-- ---------------------------------------------------------------------- -->
<P style="color: #0000ff; border=2">a view of your javascript code...</P>
<textarea style="background-color: #ffffcc;" cols=80 rows=8>
</textarea><hr/>
<P style="color: #800080">2. A bullet travels at 1325 meter's per second. 
Write a program that will input the Distance and Show the Time.</P>
<H3>bullet Input Distance <input type="text" size="20" ID="InID2" onkeyup="bulletf2(this.value)" /></H3>
<H3>bullet Output Time <input type="text" size="40" ID="OutID2" /></H3>

**Nile** · 03-01-2009, 02:42 AM

Well... if were giving answers:

HTML Code:

<script type="text/javascript">
var calculation = {
  metersps: 1325,
  calcTime: function(me, outputEl){
    me.value = parseFloat(me.value);
    outputEl.value = parseFloat(me.value) / this.metersps;
  },
  calcDistance: function(me, outputEl){
    me.value = parseFloat(me.value);
    outputEl.value = parseFloat(me.value) * this.metersps;
  }
};
</script>
Distance:<br />
<input type="text" name="distance" id="inputDist" onkeyup="calculation.calcTime(this, document.getElementById('inputTime'));" />
<br /><br />
Time:<br />
<input type="text" name="time" id="inputTime" onkeyup="calculation.calcDistance(this, document.getElementById('inputDist'));" />
<br />

That one can go both ways... You can type the distance or time.

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