Get HTML code from a page

Hello, how are you? I would like you to help me with the following:

I would like to get this textbox that is on a page and display it in the app, how do I call it.

I already got the button function. which is is:

Sin título

I have already called the “buscar” button function with this block:

blocks

the script is this:

Html:

<a href="[javascript:Enviar();](about:blank)"><img id="buscar" src="[images/buscar.jpg](https://www.imeicolombia.com.co/images/buscar.jpg)" width="50" height="18" border="0" ></a>

Code:

<script language="javascript" type="text/javascript">
	<!--  if ((f.j_captcha_response.value=="")||(f.numeracion.value=="")) -->
		  
		function Enviar(){
			f=document.theForm;
		   /* if ((f.j_captcha_response.value=="")||(f.IMEI.value==""))
		      {
				document.getElementById("block").style.display = "none";
		        alert("Debe introducir todos los datos.");		        
		        f.j_captcha_response.focus(); 
		        return;
		      }*/		  
		  
		      
		    var str = f.IMEI.value;		    
			if(str.length < 15){
				document.getElementById("block").style.display = "none";
				alert("IMEI incompleto.");
				return;
			}
			
			if (validarLetras(str) == true){
				document.getElementById("block").style.display = "none";
				alert("IMEI no válido.");
				return;
			}
		
			$.blockUI({ message: '<h1><img width="100px" height="100px" src="images/cargando.gif" /></h1>' });
			
		    grecaptcha.execute('6LcdUJoUAAAAAOjd12Ll4dWpGjNsAYSPe-JmkKuG', {action: 'srtm_cpi'}).then(function(token) {
 			    	    
    			document.getElementById("id").value=token;
	      		f.submit();	
    	    });		
		}
		
		function validarLetras(imei){
   			var letras="abcdefghyjklmnñopqrstuvwxyz ";
   			imei = imei.toLowerCase();
   			for(i=0; i<imei.length; i++){
      			if (letras.indexOf(imei.charAt(i),0)!=-1){
         			return true;
      			}
   			}   			
   			return false;
		}

		function validarNumeros(e){
			tecla = (document.all) ? e.keyCode : e.which;
		    if (tecla==8){//Tecla de retroceso para borrar
		        return true;
		    }		       		    
		    pattern =/[0-9]/; // solo numeros
		    tecla_final = String.fromCharCode(tecla);
		    return pattern.test(tecla_final);			
		}	
		
		function deshabilitarMenuContextual(){	 
		   	return false 
		} 
		
		document.oncontextmenu=deshabilitarMenuContextual
		
			
		</script>

Now the function of the input is this:

HTML:

<input name="IMEI" type="text" maxlength="15" onkeypress="return validarNumeros(event)"></font></td>						
							</tr>
							<tr>
								<td height="3" colspan="2" background="images/sd.jpg"><img src="images/px.jpg" width="1" height="1"></td>
							</tr>
							<tr>
								<td height="15" colspan="2" ></td>
							</tr>
							
							<input id="id" name="id" type="hidden" maxlength="15" ">

DId You Try ?