Set a default value to jquery variable

Question

I want to set a default value to a variable.

When the body loads it runs a function which needs the variable to get the data.
The form will do the same onchange but the form elements will be hidden and added only if the user wants to see the filter options

My current code is

var grade = document.getElementById('grade').value;

If the id grade isnt available on the first load of the i want the grade to default to 0

NickSlash · Accepted Answer · 2013-03-05 23:54:27Z

1

Try this, it should default it to zero.

var grade = document.getElementById('grade') == null ? 0 : document.getElementById('grade').value;

answered Mar 5, 2013 at 23:54

NickSlash

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6 Comments

landons Over a year ago

That will give you an error: "TypeError: Cannot read property 'value' of null"

landons Over a year ago

That should do it, but this feels so unnatural. I really like it better with jQuery: var grade = $('#grade').val() || 0

John Dvorak Over a year ago

@landons that's not jQuery-specific syntax. It's just an (ab)use of the lazy or.

landons Over a year ago

@JanDvorak I should have said "Javascript framework." To that extent, all frameworks are "(ab)use[s] of the lazy"

landons Over a year ago

This is a most pointless discussion we're attempting to have here ;)

|

landons · Accepted Answer · 2013-03-05 23:55:19Z

1

Try this:

var grade = 0;
var grade_field = document.getElementById('grade');
if (grade_field)
{
    grade = grade_field.value;
}

answered Mar 5, 2013 at 23:55

landons

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