Jquery的val()函数在IE上产生的null的处理

今天在Ie下测试Jquery代码,发现在编辑填充默认值时，如果为空的字段全部显示null,但在FF和chrome下正常

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${"#input"}.val(null);

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开始在想是不是都要加上 !=null 的判断,但是总觉得代码量太大，很不舒服

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于是查看了Jquery的源文件

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val: function( value ) {
		if ( value === undefined ) {
			var elem = this[0];

			if ( elem ) {
				if ( jQuery.nodeName( elem, "option" ) ) {
					return (elem.attributes.value || {}).specified ? elem.value : elem.text;
				}

				// We need to handle select boxes special
				if ( jQuery.nodeName( elem, "select" ) ) {
					var index = elem.selectedIndex,
						values = [],
						options = elem.options,
						one = elem.type === "select-one";

					// Nothing was selected
					if ( index < 0 ) {
						return null;
					}

					// Loop through all the selected options
					for ( var i = one ? index : 0, max = one ? index + 1 : options.length; i < max; i++ ) {
						var option = options[ i ];

						if ( option.selected ) {
							// Get the specifc value for the option
							value = jQuery(option).val();

							// We don't need an array for one selects
							if ( one ) {
								return value;
							}

							// Multi-Selects return an array
							values.push( value );
						}
					}

					return values;
				}

				// Handle the case where in Webkit "" is returned instead of "on" if a value isn't specified
				if ( rradiocheck.test( elem.type ) && !jQuery.support.checkOn ) {
					return elem.getAttribute("value") === null ? "on" : elem.value;
				}
				

				// Everything else, we just grab the value
				return (elem.value || "").replace(rreturn, "");

			}

			return undefined;
		}

		var isFunction = jQuery.isFunction(value);

		return this.each(function(i) {
			var self = jQuery(this), val = value;

			if ( this.nodeType !== 1 ) {
				return;
			}

			if ( isFunction ) {
				val = value.call(this, i, self.val());
			}

			// Typecast each time if the value is a Function and the appended
			// value is therefore different each time.
			if ( typeof val === "number" ) {
				val += "";
			}

			if ( jQuery.isArray(val) && rradiocheck.test( this.type ) ) {
				this.checked = jQuery.inArray( self.val(), val ) >= 0;

			} else if ( jQuery.nodeName( this, "select" ) ) {
				var values = jQuery.makeArray(val);

				jQuery( "option", this ).each(function() {
					this.selected = jQuery.inArray( jQuery(this).val(), values ) >= 0;
				});

				if ( !values.length ) {
					this.selectedIndex = -1;
				}

			} else {
				this.value = val;
			}
		});

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这是val函数的实现

修改最后一句，将

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??this.value = val;

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改成

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???this.value = val|| "";

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就可以了