function validaCampo(objResp) {	
	var varString = new String(objResp.value);
	
	var block = '<>||[]{}()!?:;*+=~#';
	
	var i = 0; var j = 0; var verifica=0;
	var res = '';
	
	for (i = 0; i < varString.length; i++) {		
			
			cString = varString.substring(i, i + 1);	
			verifica = 0;
			for(j=0; j < block.length; j++) {
				if( cString == block.substring(j, j + 1) ) {
					verifica = 1;
				}
			}	
			if(verifica) res+= '';
			else res+= cString;
	}
	objResp.value = res;
}