禁用提交，直到表單被填充javascript

Question

我需要禁用提交按鈕，直到所有字段都填寫規則的任何提示？

window.onload = $("input[type=submit]").attr("disabled", "disabled"); 
$(function(){ 
        $("input[type=submit]").attr("disabled", "disabled"); 
        var total = document.getElementById('valor_total'), 
        descontado = document.getElementById('valor_descontado'), 
        valor_final = document.getElementById('valor_final'), 
        vendedor = document.getElementById('vendedor'), 
        cliente = document.getElementById('cliente'), 
        no_contrato = document.getElementById('contrato'), 
        validation; 

         var f_total = total.value; 
         var f_descontado = descontado.value; 
         var f_final = valor_final.value; 
         var f_vendedor = vendedor.value; 
         var f_cliente = cliente.value; 
         var f_no_contrato = no_contrato.value; 

         $("#numero_contrato").blur(function() { 

         if (f_vendedor == "0" || f_cliente == "0" || f_no_contrato == "" || f_total == "0,00" || f_final == "0,00") { 
         validation = false; 
         } else { 
         validation = true; 
         } 
         if (validation = true) { 
         $("input[type=submit]").removeAttr("disabled"); 
         } else { 
         $("input[type=submit]").attr("disabled", "disabled"); 
         } 
         }); 
       }); 

我在做什麼錯？

我想在現場ID numero_contrato功能運行用戶類型，並啓用或不提交

Answer 1

對於初學者來說，嘗試解決這個條件：

if (validation === true) { 
    $('input[type=submit]').removeAttr('disabled'); 
} else { 
    $('input[type=submit]').attr('disabled', 'disabled'); 
} 

你有一個平等是用於分配。你想要雙倍或者最好是三倍等於。但你可以完全放棄這些，因爲你使用的是布爾型：if（validation）{...}