var dataChanges = new Array();


function formData2QueryString(docForm, formatOpts, exclFlds) {
  
  var opts = formatOpts || {};
  var str = '';
  var formElem;
  var lastElemName = '';
  var skipField;
  var o;
  
  for (i = 0; i < docForm.elements.length; i++) {
    formElem = docForm.elements[i];
    skipField = false;
    try {
    		if (exclFlds != null && exclFlds[0] != "") {
    			for (ef = 0;ef < exclFlds.length; ef++) {
    				if (formElem.name == exclFlds[ef]) {
    					skipField = true;
    					break;
    				}	
    			}
    		}
    }
    catch (e) {}
    
    if (skipField) continue;
           
    switch (formElem.type) {
      // Text fields, hidden form elements
      case 'text':
      case 'hidden':
      case 'password':
      case 'textarea':
        str += formElem.name + '=' + encodeURI(formElem.value) + '&'
        break;
        
      case 'select-one':
		for (var k = 0, l = formElem.length; k < l; ++k){
			if ((o = formElem.options[k]).selected)
			str += formElem.name + '=' + encodeURI(o.value) + '&'
		}
        break;
        
      // Multi-option select
      case 'select-multiple':
        var isSet = false;
        for(var j = 0; j < formElem.options.length; j++) {
          var currOpt = formElem.options[j];
          if(currOpt.selected) {
            theVal = encodeURI((currOpt.value!="")?currOpt.value:currOpt.text);
            if (opts.collapseMulti) {
              if (isSet) {
                str += ',' + theVal;
              }
              else {
                str += formElem.name + '=' + theVal;
                isSet = true;
              }
            }
            else {
              str += formElem.name + '=' + theVal + '&';
            }
          }
        }
        if (opts.collapseMulti) {
          str += '&';
        }
        break;
      
      // Radio buttons
      case 'radio':
        if (formElem.checked) {
          str += formElem.name + '=' + encodeURI(formElem.value) + '&'
        }
        break;
        
      // Checkboxes
      case 'checkbox':
        if (formElem.checked) {
          // Collapse multi-select into comma-separated list
          if (opts.collapseMulti && (formElem.name == lastElemName)) {
            // Strip of end ampersand if there is one
            if (str.lastIndexOf('&') == str.length-1) {
              str = str.substr(0, str.length - 1);
            }
            // Append value as comma-delimited string
            str += ',' + encodeURI(formElem.value);
          }
          else {
            str += formElem.name + '=' + encodeURI(formElem.value);
          }
          str += '&';
          lastElemName = formElem.name;
        }
        break;
        
    }
  }
  // Remove trailing separator
  str = str.substr(0, str.length - 1);
  return str;
}

function makeStruct(names) {
  var names = names.split(' ');
  var count = names.length;
  function constructor() {
    for (var i = 0; i < count; i++) {
      this[names[i]] = arguments[i];
    }
  }
  return constructor;
}



function dataScan( isCompare, docForm, formatOpts, exclFlds) {
  var Item = makeStruct("id dataType value");

  var opts = formatOpts || {};
  var formElem;
  var lastElemName = '';
  var skipField;
  var o;
  var combVal;
  var itemCounter = 0;
  
  for (i = 0; i < docForm.elements.length; i++) {
    formElem = docForm.elements[i];
    skipField = false;
    combVal = "";
    try {
    		if (exclFlds != null && exclFlds[0] != "") {
    			for (ef = 0;ef < exclFlds.length; ef++) {
    				if (formElem.name == exclFlds[ef]) {
    					skipField = true;
    					break;
    				}	
    			}
    		}
    }
    catch (e) {}
    
    if (skipField) continue;
           
    switch (formElem.type) {
      // Text fields, hidden form elements
      case 'text':
      case 'hidden':
      case 'password':
      case 'textarea':
        combVal = formElem.value;
        break;
        
      case 'select-one':
		for (var k = 0, l = formElem.length; k < l; ++k){
			if ((o = formElem.options[k]).selected)
			combVal += encodeURI(o.value) + ';'
		}
        break;
        
      // Multi-option select
      case 'select-multiple':
        var isSet = false;
        for(var j = 0; j < formElem.options.length; j++) {
          var currOpt = formElem.options[j];
          if(currOpt.selected) {
            theVal = encodeURI((currOpt.value!="")?currOpt.value:currOpt.text);
            if (opts.collapseMulti) {
              if (isSet) {
                combVal += ',' + theVal;
              }
              else {
                combVal = theVal;
                isSet = true;
              }
            }
            else {
              combVal = theVal;
            }
          }
        }
        break;
      
      // Radio buttons
      case 'radio':
        if (formElem.checked) combVal = encodeURI(formElem.value);
        break;
        
      // Checkboxes
      case 'checkbox':
        if (formElem.checked) {
          // Collapse multi-select into comma-separated list
          if (opts.collapseMulti && (formElem.name == lastElemName))
            combVal += ',' + encodeURI(formElem.value);
          else
            combVal += encodeURI(formElem.value);
          lastElemName = formElem.name;
        }
        break;
        
    }
    
	if (!isCompare)
		dataChanges[itemCounter] = new Item(formElem.name, formElem.type, combVal);
	else
		if (dataChanges[itemCounter].value != combVal) return true;
	itemCounter++;
  }
  return false;
}