Calculate text boxes using the onChange event

[celley]

I would like to have some sort of script that will allow me to do the following:<br><br>Have 10 text boxes, allow the user to enter numbers and then have them calculated in an 11th text box before the form is submitted.<br><br>I know that i need to use the onChange event.....<br><br>I have a working page that uses drop-down menu's, but I want to use text boxes.<br><br>Thanks,<br>Chad<br><A HREF="mailto:celley@gobcg.com">celley@gobcg.com</A><br>

 

[iza]

you're able to do this with drop down menus and NOT with text boxes ?????!!!!!! it should be the same, except that <br>you have to use code like that to get the values from the drop downs : &quot;my_list.options[my_list.selectedIndex]. ....&quot; and for the textboxes it's only my_textbox.value ...<br>maybe i didn't get your question ??

 

[celley]

so could I do the following?&nbsp;&nbsp;I dont know enough javascript to do it.... call me dumb.<br><br>&lt;script type=&quot;text/javascript&quot;&gt;<br>function updatesum() {<br>&nbsp;document.form.sum.value =<br>(document.form.bcg1.value[document.form.bcg1.value].text-0) +<br>(document.form.bcg2.value[document.form.bcg2.value].text-0);}<br>&lt;/script&gt;<br><br><br><br>&lt;form name=&quot;form&quot; action=&quot;form2.cfm&quot; method=&quot;post&quot;&gt;<br><br>&lt;input type=&quot;text&quot; name=&quot;bcg1&quot; onChange=&quot;updatesum()&quot; &gt;<br>&lt;input type=&quot;text&quot; name=&quot;bcg2&quot; onChange=&quot;updatesum()&quot; &gt;<br><br><br>&lt;br&gt;<br>&lt;input name=&quot;sum&quot; readonly value=&quot;(not computed)&quot; size=15&gt;<br><br>&lt;/form&gt;

 

[theEclipse]

ur not dumb, just inexpirenced.<br><br>try this:<i><br>function updatesum(){<br>document.form.sum.value=<br>(document.form.bcg1.value+document.form.bcg2.value);<br>}</i><br><br>with the rest the same<br> <p>theEclipse<br><a href=mailto:eclipse_web@hotmail.com>eclipse_web@hotmail.com</a><br><a href=robacarp.webjump.com>robacarp.webjump.com</a><br>**-Trying to build a documentation of a Javascript DOM, crossbrowser, of course. E-mail me if you know of any little known events and/or methods, etc.

 

[celley]

I did what you had wrote and it adds the two as strings.&nbsp;&nbsp;I want it to add the numbers for a sum.<br><br>How would I verify that they were numeric as well?

 

[iza]

how about reading at least some docs before coding, in order to understand what we answer ???<br><A HREF="

http://developer.netscape.com/index.html"

TARGET="_new">

http://developer.netscape.com/index.html</A>

and then go to the jscript reference or the jscript guide<br>or <A HREF="

http://msdn.microsoft.com/scripting/default.htm"

TARGET="_new">

http://msdn.microsoft.com/scripting/default.htm</A>

<br>

 

[celley]

I looked on those pages but didnt find anything....

 

[iza]

it actually IS in the docs but hey, here's the code ;]<br><br>function updatesum() {<br>&nbsp;&nbsp;var first_one = parseInt(document.form.bcg1.value, 10)<br>// first_one is now either an integer in radix 10, OR it's &quot;isNaN&quot; that is a special value saying it's NOT a number<br>&nbsp;&nbsp;var second_one = parseInt(document.form.bcg2.value, 10)<br>// same for second_one<br>// btw you can use ParseFloat instead of parseInt depending on what you actually want <br><br>// ok now some checking <br>&nbsp;&nbsp;if (isNaN(first_one)) { // it's NOT a number !<br>&nbsp;&nbsp;&nbsp;&nbsp;document.form.sum.value=&quot;the 1st value has to b an integer !!&quot;<br>&nbsp;&nbsp;&nbsp;&nbsp;return false<br>&nbsp;&nbsp;}<br>&nbsp;&nbsp;if (isNaN(second_one)) {<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;... same ...<br>&nbsp;&nbsp;}<br><br>// ok now everything's fine let's set the sum field to the correct value<br>&nbsp;&nbsp;document.form.sum.value = first_one + second_one;<br>}<br><br>if this doesn't work try to replace the last line with :<br>&nbsp;var tmp= eval(&quot;first_one + second_one&quot;<br>&nbsp;document.form.sum.value = tmp;<br>but you shouldn't have to i think