Javascript表单验证无法在引导模式下运行

Question

I'm making a bootstrap modal with a form, and I have custom JavaScript field validation and it's not working, I have tried the same in a normal page without the modal and it works perfectly.

Here is the JavaScript code:

function validartitulo()
{
    var titulo = form.titulo;
    if (titulo.value == "") {
    document.getElementById("msgtit").innerHTML = "<font color='red'>Este campo é obrigatório.</font>";
    return false;
}
if(titulo.value.length <= 25){
    document.getElementById("msgtit").innerHTML = "";
    return true;
    }
        else if(titulo.value.length>25){
        document.getElementById("msgtit").innerHTML = "<font color='red'>O tamanho máximo é 25!</font>"; 
            return false;}
        }

       function validar(){
    if(validartitulo() && validarlink())
        return true;
    return false;
}

and the form :

 <form id="luForm" class="form-horizontal form-label-left input_mask"    name="form" enctype="multipart/form-data" method="POST"  action="videos/alt_vid2.php" onsubmit="return validar()">

<div class="form-group">
   <label class="col-md-4 control-label"><font color="black">Titulo: </font></label>  
   <div class="col-md-4 inputGroupContainer">
   <div class="input-group">
   <span class="input-group-addon"><i class="glyphicon glyphicon-tag"></i> </span>
  <input  style='text-align:center;' name="titulo" value="<?php echo $lin['titulo']; ?>" class="form-control"  type="text" onblur="return validartitulo()">
    </div>
  <div id="msgtit"></div>
  </div>
</div>

console error :

Uncaught TypeError: Cannot read property 'value' of undefined
at validartitulo (eval at globalEval (jquery.min.js:2), <anonymous>:3:12)
at HTMLInputElement.onblur

Answer 1

Try to change this:

function validartitulo()

Change it to:

function validartitulo(form)

And

<input  style='text-align:center;' name="titulo" value="<?php echo $lin['titulo']; ?>" class="form-control"  type="text" onblur="return validartitulo()">

Change it to:

 <input  style='text-align:center;' name="titulo" value="<?php echo $lin['titulo']; ?>" class="form-control"  type="text" onblur="return validartitulo(this.form)">

Answer 2

解决了它，这是一个未捕获的错误，因此，无论如何，有人建议我将<script> （如果在head ）移动到body ！