如果javascript函数中的条件不起作用

Question

I need to compare the values and return the message.But the message returned always. How can i do it?

Javascript:

 function Calculation() { var grid = document.getElementById("<%=gvGoodReceived.ClientID%>"); for (var i = 0; i < grid.rows.length - 1; i++) { var txtcurrentrcvamount = $("input[id*=txtrcvQuantity]") var cell = $("#gvGoodReceived").find("tr:eq(0)").find("td:eq(2)").text(); } if (txtcurrentrcvamount > cell) { alert("Receive quantity must be less or equal PO quantity"); return false; } return true; } 

Answer 1

You need to take the value of your input:

var txtcurrentrcvamount = $("input[id*=txtrcvQuantity]").val()
//                                                      ^^^^^^

Since you're comparing numbers, and val() and text() return strings, you should convert your values to numbers before doing the comparison:

if (Number(txtcurrentrcvamount) > Number(cell))

Do note that Number(someStringThatIsNotANumber) will return NaN

Answer 2

Because your scope of a variable (txtcurrentrcvamount) is limited in between for loop, That's why this not working outside the loop scope.

for more detail, you can view this post... scope of variables

For using this variable in if condition you have initialized it before the for loop ...

EDIT: Try this may this help you either. I think there some other finding to suppose you have two rows in your grid then which row value you want to check because this always return last row value ... and if there a number value for both of the variable assignment txtcurrentrcvamount ,cell then it should be work perfectly.

function Calculation() {
  var grid = document.getElementById("<%=gvGoodReceived.ClientID%>");
  var txtcurrentrcvamount ;
  var cell;
  for (var i = 0; i < grid.rows.length - 1; i++) {
    txtcurrentrcvamount = $("input[id*=txtrcvQuantity]").val();
    cell = $("#gvGoodReceived").find("tr:eq(0)").find("td:eq(2)").text();

  }
  if (Number(txtcurrentrcvamount) > Number(cell)) {
    alert("Receive quantity must be less or equal PO quantity");
    return false;
  }
  return true;
}