function preload(url){
  if(document.images){
	  var im = new Image();
	  im.src=url;
  }
}
function get_element(elm){
  if(document.getElementById){
    if(document.getElementById(elm)) var el=document.getElementById(elm);
    else return false;
  }
  else if(document.all){
    if(document.all[elm]) var el=document.all[elm];
    else return false;
  }  
  return el;
}

function clear_if_empty(){
  var val=get_element("c_message").value;
  if(val=="") get_element("c_message").value="Type your message here";
  else if(val=="Type your message here") get_element("c_message").select();
}
function is_numeric( mixed_var ) {
  if (mixed_var === '') {
      return false;
  }
  return !isNaN(mixed_var * 1);
}
function nearest_number(txt){
  var output="";
  for(var i=0;i<txt.length;i++){
    if(txt.charAt(i)=='0' || txt.charAt(i)=='1' || txt.charAt(i)=='2' || txt.charAt(i)=='3' || txt.charAt(i)=='4' || txt.charAt(i)=='5' || txt.charAt(i)=='6' || txt.charAt(i)=='7' || txt.charAt(i)=='8' || txt.charAt(i)=='9'){
      output+=txt.charAt(i);
    }
  }
  if(output=="") output='1';
  return output;
}
// return the value of the radio button that is checked
// return an empty string if none are checked, or
// there are no radio buttons
function getCheckedValue(radioObj) {
  if(!radioObj)
    return "";
  var radioLength = radioObj.length;
  if(radioLength == undefined)
    if(radioObj.checked)
      return radioObj.value;
    else
      return "";
  for(var i = 0; i < radioLength; i++) {
    if(radioObj[i].checked) {
      return radioObj[i].value;
    }
  }
  return "";
}

// set the radio button with the given value as being checked
// do nothing if there are no radio buttons
// if the given value does not exist, all the radio buttons
// are reset to unchecked
function setCheckedValue(radioObj, newValue) {
  if(!radioObj)
    return;
  var radioLength = radioObj.length;
  if(radioLength == undefined) {
    radioObj.checked = (radioObj.value == newValue.toString());
    return;
  }
  for(var i = 0; i < radioLength; i++) {
    radioObj[i].checked = false;
    if(radioObj[i].value == newValue.toString()) {
      radioObj[i].checked = true;
    }
  }
}