从 JavaScript 函数获取返回 URL 并将其作为参数发送到操作

Question

I have a JavaScript file: informacoesImportantes.js and in it I have a function that generates a destination URL to Whatsapp.

You need to get the URL and pass it as a parameter to a qrCode.do action, but apparently it's calling the qrCode even before generating the link, because it's always going empty, but when you open the browser console and print the variable, the link is there .

I'm trying to send a parameter to Action , but the parameter comes through a JavaScript function. I tried several ways with <c:set> or even directly call the :javascript after the parameter directly in the src , but without success.

informacoesImportantes.js :

function gerarUrlWhatsapp(especialidade,data,hora,medico,unidadeMedica,enderecoCompleto) {

    var texto = "Seguem dados de confirma\u00e7\u00e3o do agendamento: "+"\n"+
    " Especialidade: "+especialidade+"\n"+
    " Data: "+data+"\n"+
    " Hora: "+hora+"\n"+
    " M\u00e9dico: "+medico+"\n"+
    " Unidade "+unidadeMedica+"\n"+
    " Endere\u00e7o: "+enderecoCompleto + "\n"+
    " Informa\u00e7\u00f5es importantes:" + "\n";
    
    return "https://wa.me/?text=" + texto;
}

agendamentoDetalhe.jsp :

<div class="col-sm-3 gnm-container-qrcode">
  <script>
      var urlWhats = gerarUrlWhatsapp('${ agendamento.especialidade.dsEspecialidade}','${dateParts[0]}','${dateParts[1]}','${agendamento.nomePrestador}','${agendamento.unidadeMedica.nome}','${agendamento.unidadeMedica.enderecoCompleto}');
  </script>
    <c:set var="qrCodeUrlWhatsapp" value="${urlWhats}" />
  <img src="../qrCode.do?qrCodeUrlWhatsapp=javascript:gerarUrlWhatsapp('${ agendamento.especialidade.dsEspecialidade}','${dateParts[0]}','${dateParts[1]}','${agendamento.nomePrestador}','${agendamento.unidadeMedica.nome}','${agendamento.unidadeMedica.enderecoCompleto}');"/>
    <p>${urlWhats}</p>
</div>

struts.xml :

  <action name="qrCode" class="**" method="qrCode">
    <result name="success" type="stream">
      <param name="contentType">image/jpeg</param>
      <param name="inputName">qrCodeImage</param>
      <param name="bufferSize">4096</param>
    </result>
  </action>

AgendamentoAction.java :

public String qrCode() {
  qrCodeImage = generateQrCodeImpl.createQrCode(accessToken, qrCodeUrlWhatsapp);
}

Answer 1

You can't call a JavaScript function in the <img src= . But you can modify the value of the src attribute. If you add an id attribute to the <img> tag then you can get this element from the document using JavaScript and modify src attribute after calling a custom function.

The below script should be in the JSP file, so the EL expressions have being evaluated before the document is rendered.

<img id="qrCodeId" src="#">
<script>
   var urlWhats = gerarUrlWhatsapp('${ agendamento.especialidade.dsEspecialidade}','${dateParts[0]}','${dateParts[1]}','${agendamento.nomePrestador}','${agendamento.unidadeMedica.nome}','${agendamento.unidadeMedica.enderecoCompleto}');
   document.getElementById("qrCodeId").src="../qrCode.do?qrCodeUrlWhatsapp="+encodeURIComponent(urlWhats);
</script>