How can a input submit call a function b4 submitting

Hi I am having problem modifying some feature of my proboard forum....well I want to first of all know how can I make an input button thats type of submit and already has something assigned to onClick call a little function I made in the header...

this is the code im facing...I dont know how to link the submit button with the function....plz help..

You can a few different things here.
One - if you want to assign a button to an event such as onClick - then use input type=button, not submit.
Two, if you only want the function to run just before submitting, use the event method called onSubmit in the form tag. E.g. <form onSubmit="return checkLength()">. Notice the return statement. If your function returns a false, then the form will not be submitted. Obviosuly, a return true will submit the form.

Check out this site - http://www.htmlgoodies.com/tutors/fm.html - It goes through the all the basics of forms and javascript.

BTW - if your code is javascript, then your script tag should be written as follows: <script type="text/javascript">

Thanx...but what if the form already has a value assigned to onSubmit...



can I add two values....how?

Create a new function that contains your function calls for the onSubmit event handler.

I have tried to make the form call two functions. Everythings fine but why is the form still submitting to the location.....? I am returning false when needed but no response...what am i doing wrong?


<script type="text/javascript">
<!--
function check_post(){
var subjin;
var rtn = true;
var allinput = document.getElementsByTagName('input')
for (i=0; i < allinput.length; i++){
if (allinput(i).name == 'subject'){
subjin = allinput(i);
if (subjin.value == ""){
alert ("No Subject Specified")
rtn = false;
break;
}
}
}
return (rtn);
}
//-->
</script>

<script type="text/javascript">
<!--fag
function submit_call(theform){
var rtn2 = check_post();
if (rtn2 == true){
if (document.all || document.getElementById) {
for (i=0;i<theform.length;i++) {
var tempobj=theform.elements[i];
if(tempobj.type.toLowerCase()=="submit"||tempobj.type.toLowerCase()=="reset") {
tempobj.disabled=true;
}
}
}
}
else {
rtn2 = false;
}

return (rtn2);
}

//-->
</script>

<form action="index.cgi?board=announcements&action=post2" method="post" name="postmodify" onSubmit="submit_call(this);">