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I have some JavaScript code that gives this error
Uncaught TypeError: Cannot read property 'value' of undefined Code
var i1 = document.getElementById('i1'); var i2 = document.getElementById('i2'); var __i = {'user' : document.getElementsByName("username")[0], 'pass' : document.getElementsByName("password")[0] }; if( __i.user.value.length >= 1 ) { i1.value = ''; } else { i1.value = 'Acc'; } if( __i.pass.value.length >= 1 ) { i2.value = ''; } else { i2.value = 'Pwd'; } What does this error mean?
926
To resolve your TypeError: Cannot read properties of undefined (reading '0') , go through these steps: Ensure you are using the correct variable. Perform a simple check on your variable before using it to make sure it is not undefined. Create a default value for the variable to use if it does happen to be undefined.
The "Cannot read property 'click' of null" error occurs when trying to call the click method on a null value. To solve the error, run the JS script after the DOM elements are available and make sure you only call the method on valid DOM elements.
Educative Answers Team. According to the Mozilla website for developer documents, “the TypeError object represents an error when a value is not of the expected type.” Uncaught means that the error was not caught in the catch part of the try-catch block.
The "Cannot set properties of undefined" error occurs when setting a property on an undefined value. To solve the error, conditionally check if the value is of the expected type (object or array) or has to be initialized before setting the property on it.
Seems like one of your values, with a property key of 'value' is undefined. Test that i1, i2and __i are defined before executing the if statements:
var i1 = document.getElementById('i1'); var i2 = document.getElementById('i2'); var __i = {'user' : document.getElementsByName("username")[0], 'pass' : document.getElementsByName("password")[0] }; if(i1 && i2 && __i.user && __i.pass) { if( __i.user.value.length >= 1 ) { i1.value = ''; } else { i1.value = 'Acc'; } if( __i.pass.value.length >= 1 ) { i2.value = ''; } else { i2.value = 'Pwd'; } } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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