Check if a period '.' is present at input

Hi,

I have a script that checks the input for a mark and does not allow >20 numbers. How can I add to the following code an additional check for the period '.' so that it won't let the user input eg. 12.4?

function markvalidate(count)
{
  Form=document.addmarkfrm;
  valid=true;

  for(j=1; j<=count; j++)
  {    
    if(document.getElementById('mark-'+j).value=="") { alert("Please Enter Mark"+j); document.getElementById('mark-'+j).focus(); valid=false; return false;}
   else if(document.getElementById('mark-'+j).value!="") { if (!Markcheck(document.getElementById('mark-'+j).value) ) { document.getElementById('mark-'+j).focus(); valid=false; return false;}}
  }
return valid;
}


function Markcheck(val)
{
 if(val > 20)
 {
  alert("Please Enter the Mark Below 20");
  return false;
 }else{ return true; }
}  


function checkuploads(mark)
{
for (i=0; i<document.addmarkfrm[0].mark.length; i++)
{
if (document.addmarkfrm[0].mark[i].value!= '') { user_input = document.addmarkfrm[0].mark[i].value; }
}
if (user_input)
{
return false;
}
}

Code (markup):

Any help will be appreciated

 

you can use the function indexOf() to see if there is a period in the input.

 

What you need is a numeric validation (you don't want to permit input like 2~1,3 too; right?)

The following check does a numeric validation

if(val.search("[^0-9]")>=0)
{
//error
}

Code (markup):

This JavaScript form validation script helps in adding validations quickly.

 

I want to insert only numbers from 0.01 to 20.00 and as where I leave the period is used instead of the comma for decimal numbers

 

Man use the "indexOf()"!

javascript:var x=prompt("Enter any string");if(x.indexOf(".")==-1){alert("Good there is no '.'")}else{alert("No '.' allowed!")}

Simple!